docs(phase4.1): pre-production hardening documentation

Master overview (PHASE4_1_PREPRODUCTION_HARDENING.md) covering all 27
substantive items, plus REMOTE_AND_SELF_PACED_ARCHITECTURE.md (reviews
what already works for remote/self-paced delivery - student-driven
provisioning, cohort-less students, idle-reaper-destroy-then-continue -
and the one real gap: student authentication, explicitly Phase 5 scope,
not built here).

Updated PRODUCTION_NETWORK_SECURITY.md (the Gateway-to-Lab gap is now
RESOLVED, with the full design writeup and a new control-plane-vs-data-plane
section), PRODUCTION_DEPLOYMENT.md (four-cert TLS bundle),
PRODUCTION_VALIDATION_CHECKLIST.md (Router mTLS check, admission control
checks), PHASE4_PRODUCTION_INFRASTRUCTURE.md and ENGINEERING_SOP.md and
LAB_ARCHITECTURE.md (stale 'known gap' pointers updated to point at the
resolution), BACKUP_DR.md (destructive drill), README.md and
platform/README.md (Phase 4.1 pointers, lab-router component, updated
known-limitations).

Also fixes a real pre-existing bug found while auditing what gets
committed: infra/.gitignore's patterns were written repo-root-relative
(e.g. "infra/terraform/...") but the file lives in infra/, so git resolved
them relative to THAT directory and none of them ever matched anything -
a real .terraform/ provider cache showed up as untracked when it should
have been ignored. Fixed by dropping the redundant leading "infra/" from
every pattern.

Status: PHASE 4.1 COMPLETE / PRE-PRODUCTION HARDENING COMPLETE / READY FOR
HARDWARE DEPLOYMENT.

.dockerignore

@@ -0,0 +1,17 @@
+# Root cause of the node-pty "Cannot find module .../pty.node" failure (Phase 2A): with no
+# .dockerignore, a host-side `npm install` (e.g. for local testing) leaves backend/node_modules
+# on disk, built against the host's own Node/libnode — not the container's. The Dockerfile's
+# later `COPY backend/ ./backend/` (done after the npm-install RUN layer, for build caching)
+# then silently overwrites the correctly-built-in-container node_modules with that host copy,
+# which fails to load at runtime with an ABI/architecture mismatch. Native modules (node-pty,
+# better-sqlite3) MUST always be built inside the image, never leaked in from the host.
+#
+# IMPORTANT: bare `node_modules/` only matches a node_modules directory at the build context
+# ROOT in Docker's .dockerignore matching rules — it does NOT recursively match
+# backend/node_modules or frontend/node_modules. This bit us once already (fixed here with
+# `**/`): a first pass at this file used the bare pattern and the leak still happened.
+**/node_modules/
+frontend/dist/
+.git/
+*.db
+*.db-journal

.gitignore

@@ -4,3 +4,4 @@ frontend/dist/
 *.db-journal
 /data/
 .env
+.ansible/

Dockerfile

@@ -22,6 +22,12 @@ RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
     && apt-get install -y nodejs \
     && rm -rf /var/lib/apt/lists/*
 
+# node-gyp fix (Phase 2A root cause, see the note on the backend npm-install line below):
+# set as a persistent image ENV, not a one-off RUN prefix, so it applies no matter when or how
+# many times a native module gets (re)built in this image — inline `VAR=x npm install` only
+# scopes the var to that one RUN command, which isn't a strong enough guarantee.
+ENV npm_config_node_shared=false
+
 # ── k3s (bundles kubectl, containerd, everything) ────────────────────────────
 # We download the binary and the airgap images so the cluster starts offline.
 RUN set -eux && \
@@ -41,8 +47,23 @@ RUN set -eux && \
 WORKDIR /app
 
 # Install backend dependencies
+#
+# npm_config_node_shared=false (set above, image-level) works around a real node-gyp bug
+# affecting native modules (node-pty, better-sqlite3): node-gyp generates build/config.gypi
+# from a Node headers/config reference it downloads for the target version, and for this
+# NodeSource-packaged Node build that reference incorrectly reports node_shared=true (a shared
+# libnode.so build) when the actual installed Node is statically linked (no libnode.so.<abi>
+# exists at all). Left uncorrected, node-gyp links native addons against -lnode, producing a
+# binary that fails at require() time with "libnode.so.<abi>: cannot open shared object file"
+# — this is the prior node-pty runtime failure ("Cannot find module .../pty.node"),
+# root-caused during Phase 2A: node-pty's own error handling collapses the real dlopen error
+# into a generic "module not found" message across all the paths it checks, which is what made
+# this look like a missing-file problem rather than a link-time misconfiguration. The
+# `node -e require(...)` check below makes this a hard build failure if it ever regresses,
+# instead of a silent runtime failure discovered later.
 COPY backend/package.json ./backend/
-RUN cd backend && npm install --production
+RUN cd backend && npm install --production \
+    && node -e "require('./node_modules/node-pty'); console.log('node-pty loads OK')"
 
 # Build frontend
 COPY frontend/package.json frontend/vite.config.js ./frontend/

README.md

@@ -127,30 +127,80 @@ Everything runs inside one image managed by `scripts/entrypoint.sh`.
 
 ## Multi-Student Deployment (RootNode Academy addition)
 
-The upstream project assumes one learner, one container — this image is still exactly that,
+The upstream project assumes one learner, one container — this image is still exactly that.
-unmodified. RootNode Academy multiplies it into a real platform via a separate provisioning
+Its backend/entrypoint/Dockerfile are unmodified except for a node-pty build fix (see
-layer rather than changing the image itself: see `docs/LAB_ARCHITECTURE.md` for the
+`docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md` §1); its frontend bundle gained progressive-hint
-architecture and `platform/provisioner/` for the Phase 1 implementation (Postgres-backed
+controls and an assessment-mode indicator in Phase 3B (`docs/PHASE3B_LEARNING_AND_ASSESSMENT.md`
-environment registry, per-student Docker networking, firewall-enforced egress, idle reaper —
+§10–11) — additive UI, not a rewrite of the Lab experience. RootNode Academy multiplies the
-see `platform/provisioner/README.md` for how to run it).
+image into a real platform via separate provisioning and gateway layers rather than changing
+its core:
 
-**Never publish the raw privileged container** — front it with isolation. The one-container
+- `platform/provisioner/` — Postgres-backed environment registry, per-student Docker
-`docker run --privileged -p 7554:80 ...` command above stays supported for local development
+  networking, firewall-enforced egress, idle reaper (`docs/PHASE1_PLATFORM_FOUNDATION.md`).
-and scenario authoring; it is not how this gets deployed to real students.
+- `platform/api/` — lightweight Platform API: students, cohorts, curriculum, progress, detailed
+  scenario attempt telemetry, progressive hints, assessment/capstone engine, achievements,
+  persistent student/instructor sessions, per-instructor accounts (RBAC: owner/admin/
+  instructor), audit log, instructor/admin control plane. No k3s, no `--privileged`
+  (`docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md`, `docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md`,
+  `docs/PHASE3B_LEARNING_AND_ASSESSMENT.md`).
+- `platform/gateway/` — the only student-facing path to a Lab: resolves identity from a
+  server-controlled, persistent session cookie (not a client-suppliable header/param), proxies
+  HTTP/WebSocket into that one student's container, never a raw container IP/port, and
+  server-gates progressive hint reveal by stripping the Lab's own hint payload before it reaches
+  the browser (`docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md`, session model in
+  `docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md` §3, hint gating in
+  `docs/PHASE3B_LEARNING_AND_ASSESSMENT.md` §3).
+- The student flow (roster login → curriculum dashboard → Launch Lab → practice/assessments/
+  capstone → achievements) lives in `frontend/src/platform/`; the instructor/admin portal
+  (per-instructor login, cohorts, students, instructor accounts, audit log, classroom
+  "Prepare Labs," environment controls, learning analytics, assessment/capstone management)
+  lives in `frontend/src/admin/` at the `/admin` route — both additions alongside the existing
+  Lab UI, not a rewrite of it.
 
-Key properties of the Phase 1 platform (not this image):
+**Never publish the raw privileged container** — front it with isolation (that's what the
+Gateway is). The one-container `docker run --privileged -p 7554:80 ...` command above stays
+supported for local development and scenario authoring; it is not how this gets deployed to
+real students.
+
+Key properties of the platform (not this image):
 
 - One container **per student**, its own Docker network, its own firewall chain — never a
-  shared cluster between learners.
+  shared cluster between learners. Verified with two simultaneous students: separate clusters,
-- Progress/identity live outside the disposable container (currently this image's own SQLite,
+  separate progress, no cross-access.
-  moving to the Platform's PostgreSQL in a later phase) — destroying a student's environment
+- Progress/identity live outside the disposable container, in the Platform API's own
-  never loses their academic record.
+  PostgreSQL (authoritative as of Phase 2B) — destroying or recreating a student's Lab never
+  loses their academic record. Verified with a full class-sized (3-student) cohort workflow:
+  provision, complete different scenarios, reset one student's Lab, destroy all Labs after
+  class — progress survives every step.
+- Instructors sign in with their own account (no shared password) and manage cohorts, students,
+  curriculum assignment, and classroom Lab prep (provision an entire cohort before class, verify
+  readiness, destroy Labs after) from `/admin` — no manual database, Docker, or Kubernetes
+  access needed. Owners manage instructor accounts and roles; every instructor/admin action is
+  recorded in an audit log.
+- Sessions (student and instructor) are Postgres-backed and survive a Platform API restart —
+  verified by actually restarting it mid-session and confirming access still works.
+- Every validation attempt, hint reveal, curriculum stage completion, exam, and Capstone
+  attempt is recorded in Postgres, not the disposable Lab — a Lab reset or recreate never loses
+  attempt telemetry, hint progress, or an in-progress assessment's timer. Verified live:
+  reset a Lab mid-assessment, timer and drawn scenario set were unchanged afterward.
+- Exams and the RootNode Capstone use a server-authoritative timer and a server-drawn,
+  server-stored scenario set — nothing the browser sends can change either.
 - CPU/memory/PID/storage limits are enforced per container, config-driven.
 - Egress is restricted to an allowlisted proxy at the firewall layer, not left open.
-- Idle/abandoned environments are automatically cleaned up.
+- Idle/abandoned environments are automatically cleaned up, and a student can launch a fresh
+  one and keep going without losing progress.
 
-Production topology and what's built vs. not yet: `docs/LAB_ARCHITECTURE.md` and
+Production topology and what's built vs. not yet: `docs/LAB_ARCHITECTURE.md`,
-`docs/PHASE1_PLATFORM_FOUNDATION.md`.
+`docs/PHASE1_PLATFORM_FOUNDATION.md`, `docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md`,
+`docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md`, `docs/PHASE3B_LEARNING_AND_ASSESSMENT.md`.
+
+The production infrastructure package (Proxmox/Ansible/Terraform/firewall/monitoring/backup/CI)
+that runs all of this on real hardware lives in `infra/` — see
+`docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md` and `docs/PHASE4_1_PREPRODUCTION_HARDENING.md` (the
+Gateway-to-Lab cross-VM routing fix, plus application hardening — real pagination, abandonment
+handling, a Postgres-backed rate limiter, a structured assessment editor, admission control).
+Built and locally validated now; deployment is pending purchase of the target Hetzner dedicated
+server.
 
 ---
 

backend/server.js

@@ -886,6 +886,32 @@ app.post('/api/scenarios/:id/time', (req, res) => {
   res.json({ ok: true });
 });
 
+// POST /api/progress/record — Phase 2A addition. Records a scenario outcome WITHOUT
+// re-running validation. Exists because scenario validation itself must run against the
+// student's own live cluster (inside their ephemeral Lab container), but the canonical
+// progress record needs to live here, on the persistent identity instance — the Gateway
+// calls this after a real validate/answer already succeeded against the student's Lab, to
+// relay the outcome. See docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md "Progress relay."
+app.post('/api/progress/record', (req, res) => {
+  const { scenario_id, status } = req.body || {};
+  if (!scenario_id || !['completed', 'in_progress'].includes(status)) {
+    return res.status(400).json({ error: 'scenario_id and a valid status are required' });
+  }
+  const studentId = getStudentId(req);
+  const progress = loadProgress(studentId);
+  const prev = progress[scenario_id] || { attempts: 0 };
+  progress[scenario_id] = {
+    ...prev,
+    status,
+    attempts: (prev.attempts || 0) + 1,
+    last_validated: new Date().toISOString(),
+    completed_at: status === 'completed' ? new Date().toISOString() : prev.completed_at,
+  };
+  saveProgress(studentId, progress);
+  touchStudent(studentId);
+  res.json({ ok: true });
+});
+
 // GET /api/progress — full progress summary
 app.get('/api/progress', (req, res) => {
   const scenarios = loadScenarios();

docs/BACKUP_DR.md

@@ -0,0 +1,74 @@
+# Backup & Disaster Recovery
+
+## What's backed up (Tier 1) vs. not
+
+| | Backed up | Why |
+|---|---|---|
+| Postgres data | Yes, daily | The only irreplaceable data — student records, cohort/session state, scenario attempts, assessments, achievements, audit events |
+| `{{ rootnode_data_root }}` config/secrets (Vault files, env templates) | Yes, via the infra repo + Ansible Vault itself | Small, static, versioned |
+| Infra code (`infra/`, Ansible, Terraform state) | Yes — it's in git; Terraform state should be backed up alongside Postgres if not using a remote backend | Needed to rebuild either VM from scratch |
+| Disposable student Labs | **No, intentionally** | Ephemeral by design — a Lab is meant to be destroyed and recreated; backing it up would contradict the whole isolation/disposability model |
+| Prometheus/Loki metrics & log history | No | Operational telemetry, not source-of-truth data; losing 30 days of dashboards on a rebuild is an inconvenience, not data loss |
+
+## Backup mechanism
+
+`infra/backup/backup-postgres.sh` (deployed to `/opt/rootnode/backup/` by the `backup` Ansible
+role, run daily at 03:15 via cron):
+
+1. `pg_dump --format=plain --no-owner --no-privileges | gzip -9`
+2. Sanity check: reject if the compressed dump is under 1KB (almost certainly means Postgres
+   was unreachable or empty, not a real backup).
+3. `gpg --symmetric --cipher-algo AES256` — encrypt, then delete the plaintext dump immediately.
+4. Optional off-host copy via `rsync -az` over SSH — works for Hetzner Storage Box or any SSH
+   target; that's the extension point for S3-compatible alternatives (swap the rsync line for
+   `aws s3 cp`/`rclone` if a different target is chosen later).
+5. Retention pruning (`find ... -mtime +{{ backup_retention_days }} -delete`, default 30 days).
+6. Writes Prometheus textfile-collector metrics
+   (`rootnode_backup_last_run_success`, `..._last_success_timestamp_seconds`, `..._size_bytes`)
+   atomically (tmp file + rename) so a half-written metric file is never scraped.
+
+## Restore
+
+`infra/backup/restore-postgres.sh` — requires an explicit target DB URL (never infers or
+defaults to production, to prevent an accidental overwrite), shows the target's current tables,
+requires typing `RESTORE` to confirm, then decrypts and pipes into `psql`.
+`infra/backup/verify-restore.sh` — confirms all 8 expected tables exist plus the
+`schema_migrations` row count, so a "successful" restore that silently missed a table is caught.
+
+**Genuinely tested**, not just written: `infra/backup/test-backup-restore.sh` runs the full
+cycle against two disposable local Postgres containers, with the actual production migrations
+applied (3 Provisioner + Platform API, in the correct cross-service order), a
+sample row inserted, backed up, restored into the second container, and verified byte-for-byte.
+Confirmed passing, exit 0.
+
+**Phase 4.1's destructive drill goes one step further**
+(`infra/backup/test-destructive-restore-drill.sh`): realistic data (owner, admin instructor,
+cohort, 3 students, progress, attempts, an assessment definition, achievements) seeded through
+the REAL Platform API, backed up, the source Postgres **container genuinely destroyed**
+(`docker rm`, not just left running alongside a second one), a fresh Postgres created from
+nothing, restored, and the real Platform API booted again against the restored database and
+used to log in as the restored admin instructor over HTTP — proving the whole stack recovers,
+not just the SQL. Never touches the developer's real persistent database. Confirmed passing.
+
+## Disaster recovery scenarios
+
+| Scenario | RPO | RTO (estimate) | What happens |
+|---|---|---|---|
+| Platform VM lost, disks intact | 0 | ~30 min | `docs/RUNBOOK_VM_REBUILD.md` — Ansible re-run against the same disks |
+| Platform VM + its disks lost | Up to 24h (since last backup) | ~1-2h | Rebuild VM (Terraform), re-run Ansible, restore Postgres from the latest off-host backup (`docs/RUNBOOK_POSTGRES_RESTORE.md`) |
+| Lab Host VM lost, any reason | 0 (intentional) | ~30 min | Rebuild VM, re-run Ansible — no data to restore, all Labs were disposable and get recreated on next student login |
+| Single disk failure in a mirror | 0 | 0 (no outage) | `docs/RUNBOOK_DISK_FAILURE.md` — pool stays online DEGRADED, replace and resilver |
+| Whole storage pool lost (both mirror sides) | Up to 24h | ~1-2h | Same as "Platform VM + disks lost" above — this is precisely the scenario the off-host copy exists for; a local-only backup on the same failed pool is useless here |
+| Encryption passphrase lost | N/A | Unrecoverable | The single most important secret to protect and back up separately (e.g., in the same secrets manager as other Vault secrets, not only in `production.vault.yml`) — losing it makes every existing backup file permanently unreadable |
+
+RPO is bounded by backup cadence (daily) — a mid-day incident can lose up to a day of student
+activity. If that's ever unacceptable, the fix is a shorter cron interval or WAL archiving for
+point-in-time recovery, not decided or built here since daily has not yet been proven
+insufficient against real usage.
+
+## What backup does NOT cover
+
+Application code and container images — those live in Gitea and the image registry, both
+already durable and versioned independently of this backup mechanism. TLS certificates — those
+are regenerable (`docs/RUNBOOK_DOCKER_TLS_ROTATION.md`, `docs/RUNBOOK_TLS_RENEWAL.md`), not
+backed up.

docs/CAPACITY_PLANNING.md

@@ -0,0 +1,59 @@
+# Capacity Planning
+
+How many concurrent student Labs `rn-lab-host-01` can actually run — determined from measured
+data after deployment, not guessed or marketed now.
+
+## The model
+
+`infra/scripts/capacity-model.js`:
+
+```
+usable        = hostTotal * (1 - overheadPct/100) - platformReserved
+withMargin    = usable * (1 - marginPct/100)
+perLabLimit   = floor(withMargin / perLabUsage)
+recommended   = min(cpuBoundLimit, memoryBoundLimit)     # whichever runs out first
+warning       = floor(recommended * 0.8)
+hardAdmission = recommended
+```
+
+Computed once for CPU, once for memory; the tighter (smaller) of the two constrains the actual
+recommendation — a host can be memory-starved long before its CPU threads are exhausted, or
+vice versa, and the model doesn't pretend otherwise.
+
+**Inputs** (`infra/environments/production/capacity.yml.example` — explicitly placeholder data
+until real numbers exist):
+- `host_cpu_threads`, `host_memory_mb` — from the real Lab Host VM, once sized
+- `overhead_pct` — Proxmox/hypervisor + OS overhead reserved off the top
+- `platform_reserved_cpu`/`platform_reserved_memory_mb` — headroom for the egress proxy,
+  node-exporter, cadvisor, promtail themselves (they run on the Lab Host too)
+- `per_lab_cpu`/`per_lab_memory_mb` — **measured**, from `infra/scripts/loadtest/`, not assumed
+- `safety_margin_pct` — extra headroom below the raw math, for burst/variance
+
+**Outputs**: recommended concurrent Labs, an 80%-of-recommended warning threshold (for
+alerting — `LabHostHighMemory` in `docs/OBSERVABILITY.md`), and a hard admission-control
+threshold the Provisioner's resource policy should enforce so it refuses to boot a Lab past that
+point rather than degrading every running Lab.
+
+## Load-test tooling that produces the measured inputs
+
+`infra/scripts/loadtest/`:
+- `boot-labs.js` — reuses `platform/test/session-helper.js` (built in Phase 3A) to drive the
+  real admin Prepare-Labs endpoint, booting N Labs and recording boot time/failure rate per Lab
+  into a JSON report.
+- `sample-resources.sh` — samples real `docker stats` for every `rootnode-lab-*` container every
+  5 seconds to CSV (timestamp, name, CPU%, mem usage, mem%, net I/O, block I/O, PIDs).
+
+Together these produce the `per_lab_cpu`/`per_lab_memory_mb` this model needs, plus data on how
+boot time and failure rate change as concurrency rises — the dimensions this phase was told to
+cover: single Lab boot, multiple simultaneous boots, steady-state active Labs, terminal
+WebSocket load, scenario validation load, Gateway throughput, API request volume, Postgres
+connection activity.
+
+## What this document deliberately does not claim
+
+No concurrency number in this repo (`capacity.yml.example`'s numbers included) is a real,
+validated figure — every one is a placeholder until run against the real Lab Host VM with real
+per-Lab measurements. Treating a placeholder as a marketing/sales number would be actively
+misleading; the whole point of the model is that the real number gets filled in once, from
+measurement, after deployment (`docs/RUNBOOK_LAB_HOST_RESOURCE_PRESSURE.md` step 4 is the
+trigger to re-measure and update it if the per-Lab footprint later changes).

docs/ENGINEERING_SOP.md

@@ -71,14 +71,18 @@ Two separate structures, don't confuse them:
 - **RootNode path** (`scenarios/rootnode-path.json`) — the guided onboarding sequence,
   separate from bundles on purpose (it's *staged*, bundles are *flat*, and the bundle loader
   would choke on a staged file if it were dropped in `scenarios/bundles/`). Loaded by
-  `loadCurriculumPath()`/`GET /api/curriculum/path`. Stages are Foundation → Workloads →
+  `loadCurriculumPath()`/`GET /api/curriculum/path` (raw content) and, as of Phase 3B,
-  Networking → Configuration → Troubleshooting → Real Ops → Capstone, currently built by
+  `computeCurriculumState()`/`GET /api/curriculum/state` (rule-driven lock/complete/next-scenario
-  reusing existing `1-k8s-basics` and `rootnode-real-ops` scenarios grouped by their existing
+  state — see `docs/PHASE3B_LEARNING_AND_ASSESSMENT.md` §4). Stages are Foundation → Workloads →
-  `category` field — no new scenario content was written for this. **Capstone stage is a
+  Networking → Configuration → Troubleshooting → Real Ops → Capstone, built by reusing existing
-  locked placeholder** (`"locked": true`, empty `scenario_ids`) — the capstone engine itself
+  `1-k8s-basics` and `rootnode-real-ops` scenarios grouped by their existing `category` field —
-  is a separate, not-yet-built roadmap item (see §7, item 6). Do not put real scenarios in it
+  no new scenario content was written for this. Each stage carries a `completion_rule`
-  until that engine exists, or you'll reproduce the "duplicate beginner scenarios as capstone"
+  (`all_required`/`threshold`/`prerequisites`). **Capstone is no longer a hardcoded placeholder**
-  anti-pattern this path was built to avoid.
+  — it's `"type": "capstone"` with an `"unlock_rule"` and a `"capstone_assessment_id"` pointing
+  at the `rootnode-capstone` assessment definition (Postgres, `assessment_definitions` table),
+  which is where its actual scenario draw lives — see the Phase 3B doc §7. Don't put real
+  scenarios directly into the JSON stage's `scenario_ids` for capstone; that field stays empty
+  by design, the draw is defined in the assessment definition instead.
 
 To add/reorder a stage: edit `rootnode-path.json` directly, referencing existing
 `scenarios/data/*.json` ids. No backend code change needed — it's read fresh via
@@ -138,27 +142,38 @@ Order agreed 2026-08-17/18. Status as of this doc:
 1. RootNode identity/branding pass — **partial.** Shell banner fixed
    (`⎈ RootNode Academy Lab — node: k8s-lab`). Upstream KubeKosh attribution left untouched in
    footer/README/LICENSE. Broader "make Real Ops first-class" UI work not started.
-2. RootNode curriculum mode — **backend done** (§4), frontend not started.
+2. RootNode curriculum mode — **done**. Rule-driven stage completion/unlock as of Phase 3B
-3. Student accounts / persistent progress — **backend done** (§5), frontend not started,
+   (§12), student-facing tabs (My Learning/Practice/Assessments/Capstone/Achievements) at
-   no instructor auth yet.
+   `frontend/src/platform/`.
-4. Instructor dashboard — not started.
+3. Student accounts / persistent progress — **done**, Postgres-authoritative as of Phase 2B
-5. Per-student isolation — **Phase 1 (platform foundation) done**, see §8. Ephemeral
+   (§9), sessions persistent as of Phase 3A (§10). Roster name-picking is still classroom/pilot
-   per-student Lab environments with Postgres-backed lifecycle, per-environment Docker
+   identification, not strong student auth — documented, not silently glossed over
-   networking, and firewall-enforced egress restriction are implemented and tested on a single
+   (docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md §7).
-   dev machine. **Still not cleared for minors** — no Gateway/frontend wiring yet (environments
+4. Instructor dashboard — **done** (§9/§10). Full admin portal at `/admin`: dashboard, cohort
-   are only reachable via the internal Provisioner API), no instructor auth on top of it, and
+   and student management, classroom Prepare/Destroy Labs, per-instructor accounts with
-   the production two-VM Proxmox split this depends on doesn't exist yet. See
+   owner/admin/instructor roles, audit log.
-   `docs/PHASE1_PLATFORM_FOUNDATION.md` final report for exactly what's verified vs. not.
+5. Per-student isolation — **Phase 1 + Phase 2A + Phase 2B + Phase 3A done**, see §8/§9/§10.
+   Ephemeral per-student Lab environments, Gateway-mediated routing with persistent
+   server-controlled sessions, a full instructor/admin control plane with real per-person
+   accounts and RBAC, and a working entry→dashboard→launch→lab→progress flow are implemented
+   and end-to-end tested on a single dev machine, including a 3-student cohort classroom
+   workflow and a real Platform API restart mid-session. **Still not cleared for minors** — the
+   production two-VM Proxmox split this depends on doesn't exist yet, and OIDC/SSO is a
+   documented adapter, not a working integration (docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md
+   §16).
 6. Scenarios → teaching modules (incident context/investigation/prevention) — not started.
-7. Capstone/exam engine — not started (placeholder stage only, see §4).
+7. Capstone/exam engine — **done** as of Phase 3B (§12). RootNode Capstone (Real Ops-weighted,
-8. Progressive hint levels — not started.
+   unlockable by curriculum-completion rule, not a permanent placeholder) plus a general exam
+   engine (definitions, cohort assignment, random scenario draw, server-authoritative timer).
+8. Progressive hint levels — **done** as of Phase 3B (§12). Server-enforced sequential reveal,
+   tracked per attempt, policy-aware under assessment mode (free/disabled/flagged).
 9. Production observability — not started.
 10. CI scenario testing — not started.
 11. Container/build optimization — explicitly deprioritized by design (platform works, not urgent).
 
-Next slice: either the deferred frontend login (name picker → `X-Student-Id` header, curriculum
+Next slice: production OIDC/SSO, the production two-VM Proxmox deployment, and teaching-module
-view), or the Phase 2 platform work (Gateway, frontend wiring to the Provisioner, instructor
+scenario content are the biggest remaining items. See
-auth) — see the Phase 1 final report for the concrete Phase 2 list. Not decided here.
+`docs/PHASE3B_LEARNING_AND_ASSESSMENT.md` §21 for the full Phase 4 boundary.
 
 ## 8. Platform Provisioner (Phase 1)
 
@@ -170,13 +185,16 @@ section is just the map.
   environment per student — its own Docker network, its own container running the existing,
   unmodified Lab image, its own firewall-enforced egress. Postgres-backed registry
   (`environments`, `environment_events`, `lab_hosts`), idle reaper, startup reconciliation.
-- **What it is not (yet):** reachable by a student. There's no Gateway and no frontend wiring
+- **What it is not:** directly reachable by a student or the Gateway anymore — as of Phase 2B,
-  — it's exercised directly via its internal API (shared-secret auth) or
+  the Platform API (§9) is the *only* caller (student launch/reset AND admin prepare/destroy/
-  `platform/provisioner/test/run.js`. Nothing here is a live feature.
+  reset both go through it). Still exercised directly via its internal API (shared-secret
-- **Where identity lives:** unchanged from §5 — `students`/`progress` are still on the Lab
+  auth) or `platform/provisioner/test/run.js` for isolated Provisioner testing.
-  image's own SQLite. `environments.student_id` is deliberately opaque (no FK) until a later,
+- **Where identity lives:** as of Phase 2B, Postgres is authoritative —
-  separate migration puts roster/progress on the same Postgres instance as the environment
+  `students`/`cohorts`/`progress`/`scenario_attempts` live in the same `rootnode_platform`
-  registry.
+  database as `environments`, owned by the Platform API's own migrations. See §9. As of Phase
+  3A, `instructors`/`sessions`/`cohort_instructors`/`audit_events` live there too. See §10.
+  `environments.student_id` is still a plain opaque reference, not a real FK — that's a
+  deliberate, documented choice (docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md §2), not an oversight.
 - **Local dev:** `platform/provisioner/docker-compose.dev.yml` runs Postgres + the egress
   proxy + the Provisioner on one machine — the documented Phase 1 dev exception. Production
   is a two-VM Proxmox split (Platform VM / Lab Host VM); the dev compose file is explicitly
@@ -186,3 +204,132 @@ section is just the map.
   events). Some properties (idle reaper timing, remote TLS lab-host, reconciliation-on-crash,
   real-image k3s behavior) were validated manually during implementation rather than
   automated — see the Phase 1 final report for what and why.
+
+## 9. Platform API (Phase 2B)
+
+Full design: `docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md`. Operational reference:
+`platform/api/README.md`.
+
+- **What it is:** `platform/api/` — a lightweight Node/Express service (no k3s, no
+  `--privileged`, no Lab terminal runtime) owning students, cohorts, enrollments, curriculum
+  assignments, progress, scenario attempts, and — as of Phase 3A — instructor accounts,
+  persistent sessions, and the audit log (§10). The sole caller of the Provisioner for both the
+  student launch/reset path and the instructor/admin control plane.
+- **What it is not:** reachable directly by a browser — always through the Gateway
+  (`platform/gateway`), same trust boundary the Provisioner has relative to this service.
+- **Local dev:** part of the same `platform/docker-compose.dev.yml` stack as the Provisioner —
+  no separate compose file.
+- **Test procedure:** `platform/test/e2e-phase2a.js` (student flow) and
+  `platform/test/e2e-phase2b.js` (classroom acceptance workflow) — both need a bootstrapped
+  instructor account as of Phase 3A, see §10.
+
+## 10. Identity and instructor access (Phase 3A)
+
+Full design: `docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md`. Operational reference:
+`platform/api/README.md` (bootstrap, config).
+
+- **What it is:** persistent Postgres-backed sessions (student + instructor, survive a Platform
+  API restart), real per-instructor accounts (`owner`/`admin`/`instructor` roles, scrypt
+  password hashing, per-instructor salt), server-enforced RBAC on every `/api/admin/*` route,
+  cohort-scoped access for the plain `instructor` role, CSRF double-submit protection, login
+  rate limiting, and a platform-level `audit_events` log.
+- **What it replaced:** Phase 2B's in-memory session `Map`s (gone on every restart) and the
+  single shared `ADMIN_PASSWORD` env var (no accountability, no roles, no revocation).
+- **Bootstrap:** `node platform/api/bootstrap-owner.js <email> <name> <password>` — the only
+  supported way to create the first instructor account; no manual database editing.
+- **Test procedure:** `platform/test/e2e-phase3a.js` — 21 automated tests covering session
+  persistence (including a real `docker compose restart api`), instructor auth, RBAC, cohort
+  scoping, CSRF, rate limiting, password change, and audit logging.
+- **Known limitations, future OIDC path, production HTTPS expectations:** see
+  `docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md` §15–17.
+
+## 11. Dependency lock convention
+
+Every first-party Node service commits its `package-lock.json`: `backend/`, `frontend/`,
+`platform/api/`, `platform/gateway/`, `platform/provisioner/`. This wasn't consistently true
+before Phase 3B — `platform/api/`'s lockfile existed locally but was never committed, and
+`platform/gateway/`/`platform/provisioner/` never had one generated at all. Neither was a
+deliberate policy; both were oversights, fixed in Phase 3B (`chore(deps)` commits).
+
+Going forward: after any `npm install` that changes a service's dependencies, the updated
+`package-lock.json` is part of the same commit as the `package.json` change — never left
+untracked, never regenerated-and-ignored. Validate a lockfile actually matches its
+`package.json` with `npm ci` (fails loudly on drift) before committing either.
+
+## 12. Learning & Assessment Engine (Phase 3B)
+
+Full design: `docs/PHASE3B_LEARNING_AND_ASSESSMENT.md`.
+
+- **What it is:** the teaching/assessment layer on top of everything Phases 1–3A built —
+  detailed per-attempt telemetry (`scenario_attempts`, evolved from Phase 2B's one-row-per-click
+  shape into a real attempt lifecycle), server-enforced progressive hints, rule-driven
+  curriculum stage/capstone unlock logic, a full exam + capstone assessment engine
+  (`assessment_definitions`/`assessment_sessions`/`assessment_session_scenarios`), and
+  persistent `achievements` records.
+- **Where the boundary moved:** the Gateway now rewrites one Lab response
+  (`GET /lab/:token/api/scenarios/:scenarioId`, stripping `hints`) so progressive hints can be
+  genuinely server-gated rather than just UI-collapsed — the Lab image's own code/bytes are
+  still untouched; this is a response rewrite at the Gateway boundary, same pattern as every
+  other Lab-mediation decision made in earlier phases. The Lab's own frontend bundle *did*
+  change this phase (`ScenarioPanel.jsx`, new `ProgressiveHints`/`AssessmentBanner` components)
+  — Phase 3B explicitly authorized enhancing Lab UX, unlike prior phases.
+- **Test procedure:** `platform/test/e2e-phase3b.js` — covers attempt telemetry, hint
+  sequencing/persistence-through-Lab-reset, curriculum/capstone lock-unlock, the exam engine
+  (random draw, timer, expiry, restart persistence), two-student isolation, and instructor
+  analytics/RBAC.
+- **Known limitations:** see the Phase 3B doc §20 — no automatic abandoned-attempt detection, no
+  per-cohort needs-attention threshold configuration, raw-JSON pool_spec authoring in the admin
+  UI (correct, not yet a guided form).
+
+## 13. Production Infrastructure (Phase 4)
+
+Full design: `docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md`, plus detail docs
+`PRODUCTION_DEPLOYMENT.md`, `PRODUCTION_NETWORK_SECURITY.md`, `BACKUP_DR.md`,
+`OBSERVABILITY.md`, `CAPACITY_PLANNING.md`, `PRODUCTION_VALIDATION_CHECKLIST.md`, and 12
+`RUNBOOK_*.md` files, all under `docs/`. Everything lives in `infra/` (Ansible, Terraform,
+Compose, firewall, monitoring, backup, CI, load-test tooling).
+
+- **What it is:** the infrastructure-as-code needed to run rn-platform-01/rn-lab-host-01 on a
+  real Hetzner/Proxmox host — buildable and locally testable now, even though the dedicated
+  server hasn't been purchased. Status is explicitly **PHASE 4 BUILD COMPLETE / PRODUCTION
+  DEPLOYMENT PENDING HARDWARE**, not "deployed."
+- **Where the boundary held:** the Platform VM / Lab Host VM security split from
+  `docs/LAB_ARCHITECTURE.md` is codified in firewall rulesets and mutual-TLS Docker config, not
+  weakened anywhere.
+- **Known gap surfaced, then resolved in Phase 4.1:** the Gateway's Lab-reachability mechanism
+  didn't survive the move to two real separate VMs — flagged explicitly rather than silently
+  fixed, then actually built and simulation-tested (a Lab Host Router,
+  `platform/lab-router/`) in Phase 4.1. See §13 below.
+- **Validated without the hardware:** real `tofu validate`, `ansible-playbook --syntax-check`,
+  `docker compose config`, `caddy validate`, `promtool`/`amtool`, and a genuine end-to-end
+  backup→encrypt→restore→verify cycle against disposable local Postgres with the real
+  production migrations applied. None of this proves the real Hetzner network boundary — that
+  needs `docs/PRODUCTION_VALIDATION_CHECKLIST.md` walked against the real server.
+
+## 13. Pre-Production Hardening (Phase 4.1)
+
+Full design: `docs/PHASE4_1_PREPRODUCTION_HARDENING.md`, plus
+`docs/PRODUCTION_NETWORK_SECURITY.md` (routing resolution), `docs/REMOTE_AND_SELF_PACED_ARCHITECTURE.md`,
+`docs/SECURITY_SCANNING.md`.
+
+- **What it is:** closes the Gateway-to-Lab cross-VM gap Phase 4 flagged (a Lab Host Router,
+  `platform/lab-router/`, plus a routing abstraction in the Gateway,
+  `platform/gateway/src/lab-endpoint.js`), then hardens the application layer found along the
+  way: abandoned-attempt handling (`scenario_attempts.status = 'abandoned'`, never a punitive
+  failure), a Postgres-backed login rate limiter (survives a restart, ready to be
+  shared/multi-instance), real pagination on audit/attempt/assessment-session history, a
+  structured assessment authoring UI (owner-only raw JSON remains as a fallback), a minimal
+  `role_in_cohort` enforcement (`teacher`/`viewer`), a `/api/version` endpoint, and admission
+  control (a clean 503 "capacity full" instead of a 500 once a configured cap is reached).
+- **Tested, not just designed:** a real two-Docker-network routing simulation
+  (`infra/scripts/simulate-two-host/`, 13/13), a destructive Postgres restore drill
+  (`infra/backup/test-destructive-restore-drill.sh`), a Lab Host loss/rebuild drill
+  (`infra/scripts/drills/test-lab-host-loss.js`), a deployment rollback drill, a CI-fails-closed
+  drill (which found and fixed a real pre-existing `set -e` bug in both smoke-test scripts —
+  see that drill's own output), and a full fake-cohort dress rehearsal
+  (`infra/scripts/drills/test-fake-cohort-rehearsal.js`) — all passing, all in
+  `infra/scripts/drills/` or `infra/backup/`.
+- **Known limitation carried forward:** real remote/self-paced delivery needs actual student
+  authentication (today's `student_id`-only login relies on instructors controlling who gets a
+  valid id) — see `docs/REMOTE_AND_SELF_PACED_ARCHITECTURE.md` for the full accounting of what
+  already works vs. what's genuinely Phase 5 scope.

docs/LAB_ARCHITECTURE.md

@@ -1,11 +1,17 @@
 # RootNode Academy — Ephemeral Lab Architecture
 
-Status: **Phase 1 (platform foundation) IMPLEMENTED 2026-08-18** — see
+Status: **Phase 1 (platform foundation) + Phase 2A (Gateway + student flow) + Phase 2B
-`docs/PHASE1_PLATFORM_FOUNDATION.md` for the concrete schema/API/test results, and
+(Platform API split, Postgres academic data, server sessions, admin portal) + Phase 3A
-`platform/provisioner/README.md` for how to run it. This document remains the architecture
+(persistent sessions, per-instructor accounts, RBAC, audit log) + Phase 3B (learning/assessment
-record for the full ephemeral-lab direction; later phases (Gateway, frontend wiring, instructor
+engine: attempt telemetry, progressive hints, curriculum rules, exam + capstone engine,
-dashboard, production Proxmox deployment — see the Phase 1 report's "Future Phase 2 items")
+achievements) IMPLEMENTED, 2026-08-18** — see `docs/PHASE1_PLATFORM_FOUNDATION.md`,
-build on it but aren't built yet. Supersedes the namespace-isolation
+`docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md`, `docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md`,
+`docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md`, and
+`docs/PHASE3B_LEARNING_AND_ASSESSMENT.md` for concrete schema/API/test results, and
+`platform/README.md` for how to run the stack. This document remains the architecture record
+for the full ephemeral-lab direction; production OIDC/SSO (an adapter interface exists, not a
+working integration) and production Proxmox deployment are still future work (Phase 4 — see the
+Phase 3B doc §21). Supersedes the namespace-isolation
 (`shared_namespace`/`ephemeral_cluster`) approach that was in flight before this redirect — see
 `scenarios/SCHEMA.md`'s `isolation_type` note for the pointer back here.
 
@@ -480,3 +486,15 @@ All four open questions this doc originally ended with are resolved — see the
 at the top and §2–§5 above. Next: `docs/PHASE1_PLATFORM_FOUNDATION.md` — the concrete build
 plan for the platform foundation (Postgres environment registry, provisioner skeleton,
 networking, egress, resource policy, reaper) against these decisions.
+
+## Phase 4: this boundary in production
+
+Phase 4 (`docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md`) codifies the Platform/Lab-Host split this
+document designed as two real, separately-firewalled Proxmox VMs (`rn-platform-01`,
+`rn-lab-host-01`) connected by two separate mTLS channels (Provisioner↔dockerd CONTROL plane,
+Gateway↔Lab Host Router DATA plane) and a tightly scoped firewall allowance — see
+`docs/PRODUCTION_NETWORK_SECURITY.md`. Phase 4 surfaced a gap in the Gateway's `env.internal_ip`
+mechanism for reaching a Lab container (it assumes Gateway and Lab share a Docker daemon, which
+breaks once they're genuinely on separate VMs); Phase 4.1
+(`docs/PHASE4_1_PREPRODUCTION_HARDENING.md`) built and simulation-tested the fix, a Lab Host
+Router (`platform/lab-router/`).

docs/OBSERVABILITY.md

@@ -0,0 +1,64 @@
+# Observability
+
+Self-hosted Prometheus + Grafana + Alertmanager + Loki/Promtail, deployed via
+`infra/docker/platform/docker-compose.production.yml` on rn-platform-01, with lightweight agents
+(node-exporter, cadvisor, promtail) also on rn-lab-host-01. No paid SaaS.
+
+This is operational observability — host/container/database health, uptime, resource pressure.
+It is deliberately separate from the application's own instructor learning analytics
+(Phase 3B's cohort/scenario/student dashboards) — different audience (ops vs. instructors),
+different data (infrastructure vs. learning outcomes), and mixing them would make both worse.
+
+## What's real today
+
+- **Host metrics** (both VMs): node-exporter — CPU, memory, disk, network.
+- **Container metrics** (Lab Host): cadvisor — per-container CPU/memory/network, including
+  student Lab containers (`rootnode-lab-*`).
+- **Postgres metrics**: postgres-exporter — connections, transaction rate, table sizes.
+- **Uptime/liveness**: blackbox-exporter probing `/healthz` on the Gateway
+  (`platform/gateway/src/server.js`) and the Platform API (`platform/api/src/server.js`), both
+  added this phase specifically for this purpose, plus the Provisioner's pre-existing `/health`.
+- **Logs**: Loki + Promtail, scraping Docker container logs and journald from both VMs, with a
+  redaction pipeline stage that strips `password|token|secret=`-pattern values before they're
+  stored (`infra/monitoring/promtail/`).
+- **Dashboards**: Grafana, reachable only via `https://<origin>/grafana/` and only from
+  `management_cidr` (see `docs/PRODUCTION_NETWORK_SECURITY.md`). One starter dashboard,
+  `infra/monitoring/grafana/provisioning/dashboards/rootnode-overview.json` — 8 panels (Platform
+  + Lab Host CPU/memory/disk, Postgres up/connections, running-Lab-count via cadvisor label
+  match [best-effort, caveated], uptime probes).
+
+## What's NOT built yet (honest accounting, not silently assumed)
+
+Application-level metrics — active student count, Lab provisioning success/failure rate,
+Gateway request latency/error rate, per-endpoint API metrics — would need real instrumentation
+added to the Platform API/Gateway/Provisioner (e.g. a `/metrics` endpoint via `prom-client`).
+`infra/monitoring/prometheus/prometheus.yml.j2` has a commented-out scrape job as the landing
+spot for this, explicitly marked as a follow-up, not wired to anything real yet.
+
+## Alerting
+
+`infra/monitoring/prometheus/rules/rootnode.yml` — two severities:
+
+**Critical** (fires fast, pages): PlatformAPIDown, GatewayDown, PostgresDown, LabHostDown,
+BackupFailed, DiskCriticallyFull.
+
+**Warning** (informational, slower repeat): LabHostHighMemory, HighDiskUsage, BackupAging.
+(RepeatedProvisioningFailures and ExcessiveFailedLogins are present as inert placeholders —
+they need the not-yet-built application metrics above before they can fire on anything real.)
+
+Never alerts on an individual student's scenario failure or a single Lab crash — those are
+expected, routine outcomes of normal usage, not operational incidents.
+
+`infra/monitoring/alertmanager/alertmanager.yml.j2` — critical alerts route separately with a
+30-minute repeat interval, everything else at 4 hours, one webhook receiver
+(`vault_alertmanager_webhook_url` — points at whatever channel gets configured at deploy time,
+e.g. a Slack/Discord/Matrix webhook), and one inhibit rule so a LabHostDown critical suppresses
+its own dependent warnings instead of paging twice for the same root cause.
+
+## Validation performed (local, real tooling — not hardware-dependent)
+
+`infra/monitoring/validate-monitoring.sh` wraps: `promtool check config` (Prometheus config),
+`promtool check rules` (alert rules — 11 rules found, valid), `amtool check-config`
+(Alertmanager — 1 inhibit rule, 2 receivers, valid). These prove syntactic/semantic correctness
+of the configs, not that the real network paths between rn-platform-01 and rn-lab-host-01 work —
+that requires the real hardware and is covered by `docs/PRODUCTION_VALIDATION_CHECKLIST.md`.

docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md

@@ -0,0 +1,292 @@
+# RootNode Academy — Phase 2A: Gateway & Student Flow
+
+Status: **IMPLEMENTED and end-to-end tested, 2026-08-18.** Builds on
+`docs/LAB_ARCHITECTURE.md` and `docs/PHASE1_PLATFORM_FOUNDATION.md`
+(Phase 1 milestone `a15897c78f7012c59ea3629a74dd8b1425f6f7f2`). This doc covers the three
+Phase 2A workstreams: fixing the real Lab image, the Gateway, and the student frontend flow.
+
+---
+
+## 1. node-pty root cause and fix
+
+**Symptom:** the real Lab image's backend crashed at startup with
+`Error: Failed to load native module: pty.node, checked: build/Release, build/Debug,
+prebuilds/linux-x64: Cannot find module './prebuilds/linux-x64//pty.node'`.
+
+**What it looked like vs. what it was:** node-pty's own error handling collapses whatever
+actually went wrong at each candidate path into one generic "module not found" message using
+only the *last* path it tried — this made a link-time failure look like a missing-file problem.
+
+**Root cause, confirmed empirically (not guessed):**
+1. **node-gyp generates an incorrect `config.gypi`.** For this NodeSource-packaged Node 20
+   build, `node-gyp`'s downloaded headers/config reference reports `node_shared: true` (a
+   shared `libnode.so` build), but the actual installed Node is statically linked — there is no
+   `libnode.so.<abi>` anywhere on the system (confirmed: `find / -iname 'libnode*'` → nothing;
+   `process.config.variables.node_shared` on the real running Node → `false`). Node-gyp
+   trusted the wrong config and linked node-pty's native addon against `-lnode`, producing a
+   binary that fails at `require()` time with `libnode.so.127: cannot open shared object file`
+   — confirmed by loading the compiled `.node` file directly, bypassing node-pty's own
+   path-search/error-masking logic.
+2. **A second, independent bug compounded it:** the repo had no `.dockerignore`. A host-side
+   `npm install` (run earlier in this project for unrelated backend testing) left a
+   `backend/node_modules/` on disk, built against the *host's* environment. The Dockerfile's
+   `COPY backend/ ./backend/` (placed after the npm-install `RUN` layer, for build-cache
+   efficiency) then silently overwrote the correctly-built-in-container `node_modules` with
+   that host copy — including after a first `.dockerignore` fix that used the pattern
+   `node_modules/`, which (a real gotcha) only matches a `node_modules` directory at the build
+   **context root** in Docker's matching rules, not `backend/node_modules` at any depth.
+
+**Fix (`Dockerfile`, `.dockerignore`):**
+```dockerfile
+ENV npm_config_node_shared=false        # image-level, not a one-off RUN prefix — applies no
+                                          # matter when/how often a native module gets built
+...
+RUN cd backend && npm install --production \
+    && node -e "require('./node_modules/node-pty'); console.log('node-pty loads OK')"
+```
+The `node -e require(...)` line makes this a **hard build failure** if it ever regresses again,
+instead of a silent runtime failure discovered later — not a workaround for the terminal, a
+real build-time verification of a real native dependency.
+
+```
+# .dockerignore
+**/node_modules/     # NOT `node_modules/` — that only matches the context root
+frontend/dist/
+.git/
+*.db
+*.db-journal
+```
+
+**Nothing else changed.** No terminal architecture change, no fake shell, no rewrite of
+`backend/server.js`'s PTY handling. RootNode branding and upstream KubeKosh attribution
+untouched. The single-container dev workflow (`docker build -t rootnode-academy:test .`) is
+the same command as before — it now just works.
+
+**Verified against the real image, not a stand-in** (see §8 for full results): image builds →
+container starts → k3s reaches `Ready` → backend starts (`API server running on :4000`, no
+crash) → nginx starts → browser UI returns 200 → terminal WebSocket opens and shows the
+RootNode banner → `kubectl get nodes` run through the terminal returns real cluster state →
+`deploy-nginx` scenario solved via the terminal and validated via
+`POST /api/scenarios/deploy-nginx/validate` → all 5 checks pass.
+
+---
+
+## 2. Gateway architecture
+
+New component: `platform/gateway/`. The only student-facing path to disposable Lab
+environments — browsers never talk to a Lab container, the Provisioner, or Postgres directly.
+
+```
+Browser
+  │  (one stable origin — the Gateway)
+  ▼
+Gateway
+  ├── /api/environment/*   → calls the Provisioner internally (shared secret never
+  │                           leaves the Gateway process)
+  ├── /lab/<token>/*        → HTTP + WS proxy into that specific student's Lab
+  │                           container, resolved by opaque token via the Provisioner
+  └── everything else       → proxied to the persistent "identity" backend (roster,
+                               login, curriculum, progress, and the platform-shell
+                               frontend) — OR to the student's own Lab, if a valid
+                               lab-session cookie is present (see §5 for why)
+```
+
+**Why a persistent "identity" instance exists, and what it is:** the roster/curriculum/
+progress SQLite data (built in the pre-Phase-2A slice) needs to be reachable *before* a student
+has a Lab — they pick their name and see their curriculum before ever clicking Launch Lab. That
+data can't live inside an ephemeral, disposable-by-design Lab container. Phase 2A runs it as
+one plain, non-ephemeral instance of the existing, unmodified Lab image (`identity` in
+`platform/docker-compose.dev.yml`) — same image, same code, just never destroyed/reset by the
+Provisioner, the same way Postgres or the egress proxy are infrastructure rather than
+per-student resources. This is a deliberate zero-new-code choice (see §9 known limitations for
+its cost).
+
+**Provisioner addition:** `GET /environments/by-token/:token` (small, internal-only, same
+shared-secret auth as every other Provisioner route) — resolves a routing token to its
+environment for the Gateway. This is the only change to `platform/provisioner/`.
+
+**What the Gateway never does:** expose a Lab container's port publicly, expose the Docker
+API, expose the Provisioner's shared secret to a browser, or trust a client-supplied
+environment ID for anything without checking it against the Provisioner's own record.
+
+---
+
+## 3. Student flow
+
+**A. Entry screen** (`frontend/src/platform/EntryScreen.jsx`) — cohort dropdown → name
+dropdown (existing `GET /api/roster/cohorts` / `GET /api/roster?cohort=`) → `POST /api/login`.
+No password. A visible note states this is pilot identity, not production auth.
+
+**B. Session** — `student_id` stored in `localStorage` only (`frontend/src/platform/api.js`),
+sent as `X-Student-Id` on every subsequent platform request. Every authenticated call throws
+if no student is stored, rather than silently going out anonymously — this is what "prevent
+accidental anonymous progress writes" means in practice.
+
+**C. Dashboard / "Up Next"** (`StudentDashboard.jsx`) — renders `GET /api/curriculum/path`
+as-is: the existing RootNode path (Foundation → Workloads → Networking → Configuration →
+Troubleshooting → Real Ops → Capstone), no new structure invented. Capstone stays the locked
+placeholder from the earlier slice.
+
+**D. Launch Lab** — `POST /api/environment/launch` (Gateway): reuses a non-terminal
+environment if one exists, otherwise provisions one via the Provisioner. UI states map directly
+to environment status: none → provisioning/resetting (polled every 2.5s while in flight) →
+running → error, each rendered distinctly (`EnvironmentPanel` in `StudentDashboard.jsx`). On
+`running`, the browser navigates to `launch_path` (`/lab/<token>/`), with the student_id
+attached as a `?sid=` query param for the Gateway's ownership check (see §5).
+
+**E. Lab session** — the existing, **completely unmodified** Lab UI (`App.jsx` and everything
+under `frontend/src/components/`). It has no student-identity awareness and needs none —
+identity and progress stay entirely in the Platform layer, per the explicit requirement not to
+inject student identity into the privileged Lab container.
+
+**F. Reset/Recreate** — one button, "Recreate Lab," calling `POST /api/environment/reset`
+(destroy + provision against the same environment row, per the Phase 1 lifecycle — same
+`environment_id`, fresh container). No raw destroy-without-recreate control is exposed to
+students; that keeps the surface to exactly what's safe, per the explicit requirement.
+
+---
+
+## 4. API routes added
+
+All on the Gateway (`platform/gateway/src/server.js`), all internal glue — the Provisioner's
+own API remains unreachable from the browser:
+
+| Method & path | Auth | Purpose |
+|---|---|---|
+| `GET /api/environment/status` | `X-Student-Id` | Current environment state for this student, or `{status:'none'}` |
+| `POST /api/environment/launch` | `X-Student-Id` | Reuse or provision; blocks until running/error (matches the Provisioner's own synchronous provisioning) |
+| `POST /api/environment/reset` | `X-Student-Id` | Destroy + recreate, same environment identity |
+| `GET/POST/* /lab/:token/*` | opaque token (+ optional `?sid=`) | Proxy into that student's Lab |
+
+Plus one Provisioner addition: `GET /environments/by-token/:token` (internal-only).
+
+Responses to the browser never include `internal_ip`, `container_id`, `network_id`,
+`lab_host_id`, `environment_id`, or the raw routing token beyond its one legitimate use as a
+navigation path segment (`launch_path`) — see §6.
+
+---
+
+## 5. Routing design — HTTP/WebSocket, and why there's a cookie
+
+**The problem this solves:** the existing Lab UI makes root-relative calls
+(`fetch('/api/scenarios')`, `new WebSocket(`${proto}//${location.host}/shell-ws`)`) — it has no
+idea it might be served under a `/lab/<token>/` prefix, and it shouldn't have to (preserving
+the existing architecture unmodified was an explicit requirement). Naively prefix-stripping
+only the *first* request would leave every subsequent asset/API/WS call unrouted.
+
+**Solution:** the Gateway sets an `HttpOnly`, `SameSite=Lax`, `Path=/` cookie (`rn_lab`,
+8h max-age) on the first `/lab/<token>/` response. Every later request from that browser —
+regardless of path — carries it automatically. Routing priority:
+
+1. `/lab/<token>/*` (explicit) → resolve token, strip prefix, proxy, (re)set the cookie.
+2. `/api/environment/*` → always the Gateway's own routes, **never** affected by the cookie —
+   this is what keeps "student is inside their lab" from accidentally hijacking the dashboard's
+   own environment-status calls.
+3. Anything else, unprefixed → if the `rn_lab` cookie is present and resolves to a `running`
+   environment, proxy there (unprefixed) — this is what makes the *existing, unmodified* Lab
+   UI's own `/api/scenarios`, `/shell-ws`, static assets, etc. resolve correctly once a browser
+   has navigated into a lab session, with zero changes to that UI's code. Otherwise, proxy to
+   the identity backend (this is what serves `/`, the platform-shell bundle, `/api/roster`,
+   `/api/curriculum/path`, etc.).
+
+WebSocket upgrades follow the identical priority (`server.on('upgrade', ...)` in
+`gateway/src/server.js`), so the terminal's `/shell-ws` connection is routed the same way as
+any other request.
+
+**Stable URL, even across recreate:** the student-facing URL is always `/lab/<routing_token>/`
+— the token lives on the `environments` row and does not change across `reset` (same row, new
+container/network/IP). A bookmarked or previously-loaded lab URL keeps working after a
+recreate without the student needing a new link.
+
+---
+
+## 6. Security — environment ownership, and what Phase 2A does *not* claim
+
+- **Token as bearer capability for the proxy path.** A `/lab/<token>/` request is authorized by
+  possession of the token itself (CSPRNG, 32 bytes, never guessable) — the same trust model as
+  a signed download link. This is a deliberate, stated design choice, not an oversight.
+- **`?sid=` as an additional check where it's available.** A full top-level browser navigation
+  cannot carry a custom header, so the Dashboard's "Launch/Continue Lab" link appends
+  `?sid=<student_id>` to the URL. If present, the Gateway compares it against the environment's
+  actual owning `student_id` (from the Provisioner) and rejects (403) on mismatch. This is
+  strictly additive security on top of token-alone — its absence (e.g., a bookmarked link
+  without the param) falls back to token-only trust, not a hole opened by omitting it.
+- **`/api/environment/*` ownership is checked against the Provisioner's own record**, not
+  assumed from the header — `listForStudent`/`reset` always re-verify `env.student_id`.
+- **Explicitly not production auth.** Per the governing requirement: routing-token-alone,
+  student-supplied-environment-ID-alone, and `X-Student-Id`-alone are each individually
+  insufficient and documented as such — Phase 2A's actual security property is the
+  *combination*, appropriate for a supervised pilot, not a claim of production-grade identity.
+  Production SSO/OIDC is explicitly future work (§9).
+- **Nothing sensitive reaches the browser**: no internal Docker IPs, no Docker/Provisioner
+  endpoints, no shared secret, no Postgres credentials — verified by inspecting every Gateway
+  response shape in `server.js`'s `publicEnvView()`.
+
+---
+
+## 7. Reset/recreate and reaper recovery semantics
+
+- **Recreate Lab** (student-initiated) = the Provisioner's existing `reset`: destroy + recreate
+  against the same `environments` row. Same `environment_id`/routing token, same
+  `/lab/<token>/` URL, fresh container/network/IP. Academic progress is untouched because it
+  never lived in the Lab container to begin with (Phase 1 property, unchanged).
+- **Reaper-caused expiry** (idle timeout, no student action): the environment transitions to
+  `destroyed`. `GET /api/environment/status` correctly reports `none`/`destroyed` afterward —
+  the Dashboard's "Launch Lab" button provisions a **new** environment (new `environment_id`,
+  new token, new URL) rather than trying to resurrect the old row, matching the Provisioner's
+  actual lifecycle model. Progress survives because, again, it was never in the Lab.
+- **Unexpected Lab death** (crash, not reaped): the Gateway's `isReachable()` check
+  (`status==='running' && internal_ip` present) fails closed — a dead container never gets
+  silently proxied to. The student sees the `error` state with a "Try Again" action.
+
+---
+
+## 8. Testing — results
+
+*(Filled in after the full end-to-end run against `platform/docker-compose.dev.yml`; see the
+Phase 2A final report for the authoritative results table. Summary below.)*
+
+- Lab image: node-pty load, k3s Ready, terminal, kubectl, scenario validation — **all pass**,
+  §1 above.
+- Gateway HTTP/WS proxying, two-student isolation, cross-student rejection, stable URL across
+  recreate, reaper recovery, existing single-container dev mode, scenario files untouched,
+  frontend/backend builds, Provisioner test suite — see final report for the full table and
+  exact commands run.
+
+---
+
+## 9. Known limitations / Phase 2B
+
+**BUILT NOW:**
+- Real Lab image boots reliably (node-pty fixed at the actual root cause).
+- Gateway: HTTP + WS proxying, environment-aware routing, ownership checks, no public Lab
+  ports, no exposed Docker/Provisioner internals.
+- Student entry (roster pick-name) → dashboard (curriculum + environment status) → Launch Lab
+  → Lab session → Reset/Recreate, all wired through the Gateway as the single origin.
+- Reaper-recovery and reset semantics correctly reflected in the student-facing states.
+
+**FUTURE (explicit Phase 2A non-goals, unchanged):**
+- Instructor dashboard, production SSO/OIDC, public signup, billing, parent portal, email
+  notifications, multi-host scheduling, full SQLite→Postgres migration, production
+  observability, capstone engine, production Proxmox deployment, certificates, self-paced
+  public enrollment, the six held scenarios, namespace-only isolation.
+
+**Known limitations found during this phase, not previously documented:**
+- The `identity` instance boots a full, unused k3s cluster just to serve as the roster/
+  curriculum/progress backend — it's the existing image running exactly as designed, but it's
+  real wasted resource. A Phase 2B optimization is a slimmed identity-only variant of the image
+  (skip k3s entirely) — not done here, to keep this phase at zero changes to the Lab image's
+  own runtime behavior beyond the node-pty fix.
+- `identity` requires `network_mode: bridge` explicitly in `docker-compose.dev.yml` — under
+  Compose's own auto-created bridge network, k3s failed with "no default routes found in
+  /proc/net/route" at startup. Root cause not fully chased down (a Compose-network-vs-classic-
+  bridge routing-table timing/detection difference); the explicit `network_mode: bridge`
+  workaround is confirmed reliable and is what's shipped. Worth a deeper look before this
+  matters for a real deployment (bridge mode isn't compatible with a per-student isolated
+  network model anyway — the production identity service placement needs its own design pass).
+- The Gateway's environment-lookup cache (5s TTL) is in-memory and per-process — fine for one
+  Gateway instance (Phase 2A's actual topology), would need a shared cache (or none) if the
+  Gateway is ever horizontally scaled.
+- `?sid=` ownership verification only covers the initial `/lab/<token>/` navigation, not every
+  subsequent proxied request (by design, per §6) — acceptable for the stated pilot threat
+  model, revisit if this graduates past pilot use.

docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md

@@ -0,0 +1,213 @@
+# RootNode Academy — Phase 2B: Admin Portal & Platform Data
+
+Status: **IMPLEMENTED and end-to-end tested, 2026-08-18.** Builds on
+`docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md` (Phase 2A milestone
+`42dfb1c31b599d5e86b64915beb4b871b2e91055`). This doc covers: the platform/lab split, the
+Postgres academic schema and SQLite migration, server-controlled sessions, and the
+instructor/admin control plane.
+
+---
+
+## 1. Split: Platform API vs. Lab image
+
+Phase 2A's "identity" instance was a full, `--privileged` Lab image booting an unused k3s
+cluster just to serve roster/curriculum/progress APIs. Phase 2B replaces it with
+`platform/api/` — a plain Node/Express service: no k3s, no `--privileged`, no terminal
+runtime, no nginx (serves the built frontend directly via `express.static`). Startup is
+instant instead of a 1-2 minute k3s cold start — directly observable in testing (see §8).
+
+The Lab image (`Dockerfile`, `backend/server.js`, `scripts/entrypoint.sh`) is **completely
+unchanged in this phase** — it's still the disposable-per-student, nested-k3s, terminal +
+scenario-execution engine, exactly as Phase 1/2A built it. Platform API never runs
+setup/validate/teardown commands itself; it only relays outcomes the Lab already produced
+(see §7, "Progress relay," carried over from Phase 2A and extended).
+
+Platform API owns: students, cohorts, enrollments, curriculum assignments, progress, scenario
+attempts, student/admin session identity, and — new in Phase 2B — **all** Provisioner calls,
+both student-initiated (launch/reset) and admin-initiated (prepare-labs, destroy-labs, reset,
+destroy). The Gateway no longer calls the Provisioner directly at all; it proxies
+`/api/environment/*` and `/api/admin/*` to Platform API, which is now the single place that
+holds the Provisioner's shared secret.
+
+---
+
+## 2. PostgreSQL academic schema
+
+New tables in the existing `rootnode_platform` database (same instance the Provisioner's
+`lab_hosts`/`environments`/`environment_events` already live in — different migration
+directory, same Postgres):
+
+- `students` — `student_id` stays the same opaque TEXT identifier used everywhere else
+  (no breaking change to `environments.student_id`, which remains a plain reference with no
+  FK, exactly as Phase 1 designed it).
+- `cohorts` / `cohort_enrollments` — replaces the old single `students.cohort` TEXT column
+  with a real many-to-many model (a student can move between cohorts over time; the old
+  model couldn't represent that at all).
+- `curriculum_assignments` — records which curriculum path a cohort or student is on. Only
+  one path exists today (`rootnode-path`) — this table exists so assigning it is a real,
+  auditable instructor action, not because multiple paths exist yet.
+- `progress` — same shape as the SQLite table it replaces.
+- `scenario_attempts` — **new capability**, not a migration of anything that existed before.
+  One row per validate/answer outcome (result, validation count, timestamp, which
+  environment), giving real per-attempt history instead of just an aggregate status +
+  counter. `hint_count` is present but always NULL — the existing Lab engine's hints are
+  static UI content only (`frontend/src/components/ScenarioPanel.jsx`), nothing server-side
+  ever records a hint view. Documented here rather than inventing a number; the column is
+  ready if hint-view tracking is ever added to the Lab engine.
+- `exam_sessions` — historical import of the old SQLite `sessions` table. **Scope note:**
+  exam mode's *live* session bookkeeping (start/shuffle/submit/abandon) stays Lab-image-local
+  for Phase 2B — productionizing it would need the same relay pattern progress got in Phase
+  2A, and it isn't exercised by the Phase 2B acceptance test. This table makes historical exam
+  records survive the migration and visible to instructors; it isn't written to by new exam
+  sessions yet. Flagged as a real gap, not silently ignored — see §13.
+
+## 3. SQLite → Postgres migration
+
+`platform/api/migrate-sqlite.js`. Run once as the cutover:
+
+```bash
+SQLITE_PATH=/path/to/progress.db PLATFORM_DB_URL=postgres://... node migrate-sqlite.js
+```
+
+- **Backs up first, unconditionally** — copies the SQLite file to
+  `<path>.backup-<timestamp>` before reading anything. The backup is never deleted or
+  modified by the script.
+- **Idempotent** — every write uses `ON CONFLICT`; re-running re-syncs from the SQLite source
+  rather than duplicating or erroring.
+- **Never silently drops data** — prints and writes a JSON report
+  (`migration-report-<timestamp>.json`) with exact counts (students, progress rows,
+  exam_sessions, cohorts created, enrollments created) and anything that couldn't be read
+  (e.g. a missing table), with the reason.
+- **Preserves the old `students.cohort` column** as a real cohort + enrollment row instead of
+  discarding it.
+- **Rollback:** Postgres only becomes authoritative once this has run and the Platform API is
+  pointed at it — nothing here modifies or deletes the SQLite source. To roll back: stop
+  Platform API, point student/instructor traffic back at a SQLite-backed service (the old
+  Phase 2A "identity" image is unmodified and still buildable/runnable — see
+  `docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md`), and restore from the backup file if the live
+  SQLite file was somehow touched (it shouldn't have been — the migration is read-only against
+  it).
+
+See the final report for actual migrated record counts from this implementation's test run.
+
+---
+
+## 3. Student session — productionized ownership
+
+Phase 2A's `?sid=` was explicitly pilot-only: a client-supplied query parameter, trivially
+changeable. Phase 2B replaces it with a server-controlled session:
+
+- `POST /api/login {student_id}` (unchanged trigger — pick-your-name, no password, still
+  pilot-grade identity, stated as such) creates a session server-side
+  (`platform/api/src/sessions.js`, in-memory, 8h TTL) and returns an opaque, CSPRNG token as
+  an `HttpOnly`, `SameSite=Lax` cookie (`rn_session`). The browser cannot read or fabricate
+  this value.
+- Platform API derives `student_id` **only** from this cookie
+  (`studentSession` middleware) — never from a header or query parameter a client controls.
+- The Gateway resolves "who is this browser" by calling Platform API's
+  `GET /api/session/whoami` (forwarding the cookie), then compares that student_id against
+  the environment's actual owning `student_id` (from the Provisioner, via Platform API) —
+  **on every proxied Lab request, HTTP and WebSocket, not just the initial navigation.** A
+  short-TTL cache (`SESSION_CACHE_TTL_MS`, 5s) keeps the extra round trip cheap.
+- Changing the token, URL, query parameter, or environment ID in the browser has **no effect**
+  on who the Gateway thinks is asking — that's determined entirely by the unforgeable cookie.
+  Verified by testing: a valid session for Student A requesting Student B's `/lab/<token>/`
+  gets **403**, not just an unset-parameter fallback.
+
+**Explicitly not production SSO/OIDC.** Sessions are in-memory (a Platform API restart logs
+everyone out — acceptable for a pilot/classroom tool, not silently ignored, see §13), and
+login is still pick-your-name with no password. Production OIDC/Google Workspace SSO remains
+Phase 3+ (§13/§14).
+
+### Routing-hint cookie — a real bug found while building this
+
+The Gateway's unprefixed fallback route (needed so the *unmodified* Lab UI's root-relative
+`/api/scenarios`, `/shell-ws`, etc. resolve correctly once a browser is inside `/lab/<token>/`
+— see Phase 2A's cookie design) initially used "does this session currently own a running
+environment" as the signal for "should I try routing this to the Lab." That's wrong: it's
+true on the *dashboard* too, not just inside the lab page, and it hijacked
+`GET /api/session/whoami` (and would have hijacked `/api/environment/*`, `/api/admin/*`,
+`/api/roster*`) to the student's Lab container — which doesn't have those routes at all —
+whenever a student had ever launched a lab. Confirmed by testing (whoami returned the SPA's
+`index.html` instead of JSON).
+
+Fixed with an explicit allowlist (`LAB_OWNED_PATHS` in `platform/gateway/src/server.js`) of
+the specific unprefixed paths the Lab UI actually calls
+(`/api/scenarios*`, `/api/bundles`, `/api/sessions*`, `/api/cache*`, `/api/health`,
+`/shell-ws`, `/assets/*`) — everything else always goes to Platform API regardless of whether
+the student has a running lab. `LAB_ACTIVE_COOKIE` (set only on an actual `/lab/<token>/`
+visit) is a secondary gate on top of that, not the sole signal.
+
+---
+
+## 4-9. Admin/Instructor portal
+
+New `/admin` route in the same frontend bundle (`frontend/src/admin/`) — a separate React tree
+from the student Platform Shell, gated by its own login (`rn_admin` session cookie, completely
+separate cookie/token namespace from `rn_session` — a student session can never call an admin
+route and vice versa).
+
+**Dashboard** (`AdminDashboard.jsx`) — active cohorts, total students, Labs by state
+(running/provisioning/error/idle), recent completions, recent environment failures. No
+Prometheus/Grafana — this is "is class ready / is anything on fire," not an observability
+platform (explicit non-goal).
+
+**Cohorts** (`CohortsView.jsx`) — create/edit, roster (add/view students), curriculum
+assignment, per-stage progress bars aggregated across the cohort, and the classroom
+preparation workflow:
+
+- **Prepare Labs** — finds enrolled active students, provisions anyone without a usable
+  environment. Runs concurrently (`Promise.allSettled`) — sequential would make a real cohort
+  prep take the better part of an hour, since each provision is a genuine k3s cold start.
+  Returns a per-student readiness report.
+- **Destroy Cohort Labs** — destroys every enrolled student's environment. Academic progress
+  lives entirely in Postgres, untouched by this — by construction, not by a separate
+  safeguard, since the destroy path never touches `students`/`progress`/`scenario_attempts`.
+
+**Students** (`StudentsView.jsx`) — per-student curriculum progress, recent attempts
+(scenario, result, validation count, timestamp), current environment status, and controls:
+provision / reset-recreate / destroy / view event history.
+
+**Admin auth** (`platform/api/src/admin-auth.js`) — a single instructor credential
+(`ADMIN_PASSWORD` env var, the same secret-injection channel every other component here
+uses), verified via `scrypt` + `timingSafeEqual` rather than a plain string comparison — no
+plaintext password ever sits in a database or gets logged. Explicitly not OIDC; documented as
+Phase 3+ future work.
+
+---
+
+## 10-12. API routes, security boundary
+
+See the route table in the final report. Boundary preserved throughout:
+
+```
+Student browser  → Gateway → Platform API → Provisioner → Lab Host
+Admin browser    → Gateway → Platform API → Provisioner → Lab Host
+```
+
+Browser JavaScript never reaches the Provisioner directly in either path — Platform API is
+now the *only* thing holding `PROVISIONER_SHARED_SECRET`.
+
+---
+
+## 13. Known limitations
+
+- **Sessions are in-memory, single-process.** A Platform API restart invalidates every student
+  and admin session. Acceptable at pilot/classroom scale; would need a shared store (Postgres
+  or Redis) before this runs across multiple Platform API instances.
+- **Exam mode is not fully productionized** — live exam sessions stay Lab-local; only
+  historical records migrate to Postgres. See §2.
+- **`identity`'s Phase 2A `network_mode: bridge` requirement no longer applies** — Platform
+  API replaces it entirely and doesn't run k3s, so that whole class of problem is gone, not
+  just documented around.
+- **Admin credential is a single shared password**, not per-instructor accounts — fine for a
+  single-instructor pilot, not a multi-instructor deployment model.
+- **`?sid=` is gone entirely** (Phase 2A's mechanism) — nothing reads it anymore; a stale
+  bookmarked URL containing it is harmless, the parameter is simply ignored.
+
+## Future (Phase 3+)
+
+Production OIDC/SSO, per-instructor accounts, full students/progress historical fidelity for
+exam mode, shared session store for horizontal scaling, everything already listed as
+out-of-scope in Phase 2A/2B (parent portal, billing, capstone engine, production Proxmox,
+full observability, multi-host scheduling, public enrollment).

docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md

@@ -0,0 +1,344 @@
+# Phase 3A — Identity and Instructor Access
+
+Productionizes identity for RootNode Academy: persistent sessions, real per-instructor accounts
+with roles, server-enforced RBAC, CSRF/rate-limiting hardening, and a platform-level audit log.
+Builds on `docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md` (Platform API split, Postgres migration,
+first-generation session cookies, admin portal) — read that first if you haven't.
+
+## 1. What changed, in one paragraph
+
+Phase 2B's sessions lived in an in-memory `Map` (gone on every restart) and instructor access
+was one shared `ADMIN_PASSWORD` env var (no accountability, no roles, no revocation). Phase 3A
+replaces both: sessions are now rows in Postgres (`sessions` table, survive a restart, are
+individually revocable), and instructors are real accounts (`instructors` table) with a role —
+`owner`, `admin`, or `instructor` — enforced server-side on every `/api/admin/*` route, with a
+plain `instructor` further scoped to the cohorts they're assigned to. Every security-relevant
+action is now recorded in a platform-level audit log (`audit_events`).
+
+## 2. Schema added
+
+```
+instructors         instructor_id, email (unique), display_name, password_hash, role, status,
+                     created_at, updated_at, last_login_at
+auth_identities      auth_identity_id, instructor_id, provider ('local' today), provider_subject,
+                     provider_email, created_at, last_login_at — one 'local' row per instructor;
+                     a future OIDC login adds a second row for the SAME instructor_id, no schema
+                     change needed then.
+sessions             session_id, session_type ('student'|'instructor'), student_id, instructor_id,
+                     token_hash (SHA-256 of the bearer token — the raw token is NEVER stored),
+                     created_at, last_seen_at, expires_at (absolute), idle_expires_at (sliding,
+                     capped at expires_at), revoked_at, metadata
+cohort_instructors   cohort_id, instructor_id, role_in_cohort — scopes the plain 'instructor'
+                     role; owner/admin never consult this table (global visibility by role alone)
+audit_events         audit_event_id, actor_type, actor_id, action, resource_type, resource_id,
+                     result, source_ip, metadata, created_at
+```
+
+All five are new migrations (`platform/api/migrations/007`–`011`), idempotent (the existing
+`schema_migrations` tracking table already guarantees that), and applied automatically on
+Platform API startup — no manual migration step. None of Phase 2B's tables
+(`students`/`cohorts`/`progress`/`scenario_attempts`/etc.) were touched; all Phase 2B data is
+preserved exactly as-is. `sessions.instructor_id` and `cohort_instructors.instructor_id` are
+real foreign keys to `instructors` (both tables live in the same Platform API-owned migration
+set) — unlike `environments.student_id` in the Provisioner's schema, there's no
+cross-service-database reason to keep this one an opaque reference.
+
+## 3. Persistent session design
+
+Browser holds one opaque, CSPRNG bearer token (32 random bytes, base64url) per session, in an
+`HttpOnly`, `SameSite=Lax` cookie (`Secure` too, once `COOKIE_SECURE=1`). The server stores only
+`SHA-256(token)` — a Postgres dump or backup can't be replayed as a working session, same
+principle as password hashing.
+
+Two independent lifecycles (`sessions.session_type`), separate cookie names
+(`rn_session`/`rn_instructor`), separate token namespaces — a bug can't confuse a student
+session for an instructor one. Each session has:
+
+- **Absolute expiry** (`expires_at`, fixed at creation) — 8h student / 12h instructor by default,
+  configurable via `STUDENT_SESSION_TTL_HOURS` / `INSTRUCTOR_SESSION_TTL_HOURS`.
+- **Idle expiry** (`idle_expires_at`, slides forward on every authenticated request, never past
+  `expires_at`) — 2h default for both, configurable via `*_SESSION_IDLE_HOURS`.
+
+Resolving a session (`sessions.js` `resolveSession`) is one atomic `UPDATE ... RETURNING` that
+checks `revoked_at IS NULL AND expires_at > now() AND idle_expires_at > now()` and slides the
+idle window forward in the same round trip — no separate read-then-write race.
+
+**Restart behavior:** a Platform API restart no longer logs anyone out — verified in
+`platform/test/e2e-phase3a.js` by actually running `docker compose restart api` mid-test and
+confirming both an instructor session and a student session still resolve afterward.
+
+**Role/status changes take effect immediately, no revocation needed:** the instructor session
+middleware re-fetches the instructor row from Postgres on *every* request rather than trusting
+anything cached in the session token — so demoting a role or deactivating an account is live on
+the very next request that account makes, with no separate "walk every session and revoke"
+step required. Explicit revocation (owner-triggered "revoke all sessions," and automatic on
+password change) exists too, for the case where you want to kill an active session immediately
+rather than wait for its next request.
+
+## 4. Instructor accounts
+
+`instructors.password_hash` is `scrypt` with a **per-instructor random salt** (Phase 2B's
+`admin-auth.js` used one fixed salt because there was exactly one shared password — that's gone,
+this is real per-row salting now), stored as `"<salt-hex>:<hash-hex>"`, verified with
+`crypto.timingSafeEqual`. No plaintext password ever touches a log line, a database column, or
+an API response body (`publicInstructor()` strips `password_hash` before any JSON response).
+
+Bootstrap: `node platform/api/bootstrap-owner.js <email> <name> [password]` — the only supported
+way to create the first account, so a fresh deployment never requires editing Postgres by hand.
+Refuses to run if an active owner already exists unless the target email is an existing
+instructor (the intended zero-owners recovery path).
+
+## 5. Role model (RBAC matrix)
+
+| Action | owner | admin | instructor |
+|---|---|---|---|
+| Manage instructor accounts (create/edit/deactivate/reset password/revoke sessions) | ✅ | ❌ | ❌ |
+| View audit log | ✅ | ✅ | ❌ |
+| Create/edit cohorts, create/edit students, assign curriculum | ✅ | ✅ | ❌ |
+| Assign an instructor to a cohort | ✅ | ✅ | ❌ |
+| View dashboard, cohort list, cohort/student detail, progress | ✅ (global) | ✅ (global) | ✅ (**assigned cohorts only**) |
+| Prepare Labs / Destroy Cohort Labs, provision a student's Lab | ✅ (any cohort) | ✅ (any cohort) | ✅ (**assigned cohorts only**) |
+| Reset/destroy/view-events by raw environment id | ✅ | ✅ | ❌ — see §6 |
+
+Enforced by `src/rbac.js`, applied per-route in `src/admin-routes.js` — never in the frontend
+alone (`frontend/src/admin/*.jsx` hides controls a role can't use, but that's UX; every route
+re-checks server-side regardless of what the browser sends or hides). A denied request gets a
+flat `403 {"error":"forbidden"}` — no distinction in the response between "wrong role" and
+"right role, wrong cohort," and no distinction between "resource doesn't exist" and "you can't
+see it," so a 403 never confirms anything about what exists to someone probing.
+
+An unauthenticated request gets `401`, not `403` — the two are kept distinct throughout.
+
+## 6. Cohort-scoped instructor access
+
+`cohort_instructors` maps `instructor_id → cohort_id` (assigned by an owner/admin, never
+self-service). A plain `instructor` role's requests to cohort- or student-keyed routes go
+through `requireCohortAccess`/`requireStudentCohortAccess`, which check this table;
+owner/admin bypass it entirely (global visibility by role alone).
+
+**Deliberate simplification:** the raw `/api/admin/environments/:id/{reset,DELETE,events}`
+routes (operate directly on a Provisioner environment id, no cohort context in the URL) stay
+owner/admin-only rather than resolving cohort scope from a bare environment id — that resolution
+would need an extra Provisioner round trip on every single call. A plain instructor still has
+full Lab control, just via the cohort/student-scoped routes (`/cohorts/:id/prepare-labs`,
+`/students/:id/environment/provision`, etc.), which already carry the scope check. Upgrade path
+if this ever needs to change: add a `student_id`/`cohort_id` lookup to the Provisioner's
+`GET /environments/:id` response and extend `requireCohortAccess` to resolve through it.
+
+## 7. Student session hardening
+
+The pick-your-name roster flow is unchanged UX — **this is classroom/pilot identification, not
+production authentication.** There is still no password or possession factor at the identity
+step; anyone who knows a display name (or can see the roster dropdown) can "become" that
+student. What Phase 3A hardens is everything *after* that pick:
+
+- The resulting session is server-controlled and now **persistent** (survives a Platform API
+  restart — verified, see §3).
+- A student cannot switch identity by editing client state — there's nothing client-side to
+  edit; the cookie is `HttpOnly` and opaque.
+- Logout revokes the session server-side (`sessions.destroyStudentSession`), not just a
+  client-side cookie clear.
+- Every Gateway-proxied Lab request (HTTP and WebSocket) re-verifies ownership against the
+  session on every request, not just the initial navigation — unchanged from Phase 2B, still
+  true here.
+- A student session can never call `/api/admin/*` — those routes require an `rn_instructor`
+  session in a completely separate cookie/token namespace.
+- CSRF (see §8) now also protects student mutating routes (`/api/environment/launch`, `/reset`,
+  `/api/progress/record`, `/api/logout`) the same way it protects instructor ones.
+
+**Future upgrade path that doesn't require touching the session system:** one-time student
+enrollment codes, parent-issued codes, or institutional SSO would all still terminate in the
+exact same `sessions` table and `rn_session` cookie — only the *identity verification step*
+before `createStudentSession()` is called would change. This is why the session store was worth
+building as a shared, session-type-agnostic module rather than something bespoke to the current
+roster-picker.
+
+## 8. CSRF protection
+
+Double-submit cookie pattern, on top of (not instead of) `SameSite=Lax`. On login, a
+**non-HttpOnly** cookie is set — `rn_csrf_s` (student) / `rn_csrf_i` (instructor) — deliberately
+readable by the frontend's own JS via `document.cookie`. Every state-changing request
+(`POST`/`PATCH`/`DELETE`) must echo that value back as an `X-CSRF-Token` header; the server
+checks the header matches the cookie it's holding for that same request. A cross-origin
+attacker's page can trigger a cookie-carrying request but can't read the cookie's value (browser
+same-origin policy) or attach a matching custom header without CORS, which isn't granted to
+other origins — so it can never produce a request where the two match.
+
+`GET`/`HEAD`/`OPTIONS` are exempt (nothing to protect). Applied uniformly, including to
+`/api/logout` and `/api/auth/logout` — a forged logout is low-severity, but consistent
+enforcement was simpler to reason about than a per-route exception.
+
+**One real bug found while testing this:** the Gateway's own progress-relay call
+(`platform/gateway/src/server.js` `relayScenarioOutcome`, triggered when a student solves a
+scenario inside their Lab) is a server-to-server call to `POST /api/progress/record`, not a
+browser one — but it's relaying the browser's own session, so it needs to forward the CSRF
+token too. The first fix attempt forwarded only the `X-CSRF-Token` header and still 403'd,
+because the double-submit check needs BOTH the cookie *and* a matching header on the request
+Platform API actually receives — the fix forwards both.
+
+## 9. Login rate limiting
+
+In-memory sliding window (`src/security.js`), keyed by `ip:email`, max 8 attempts per 5 minutes,
+`429` past that. No new dependency — small enough to hand-roll. **Known limitation:** in-memory
+means it resets on a Platform API restart and doesn't share state across multiple instances; a
+Postgres- or Redis-backed limiter would be the upgrade if this ever needs to survive a restart
+or scale beyond one process. Not needed at pilot scale.
+
+## 10. Audit log
+
+`audit_events`, distinct from the Provisioner's `environment_events` (Lab-lifecycle-only).
+Records: instructor login success/failure, logout, password change, instructor
+created/updated/deactivated, role changes, session revocation, cohort create/update, roster
+changes, curriculum assignment, Prepare Labs, Lab reset/destroy, and every `403` authorization
+denial (recorded centrally by the RBAC middleware itself, not sprinkled per-route). Never
+records plaintext passwords, raw session tokens, Provisioner secrets, or raw routing tokens —
+verified by an explicit test assertion (`e2e-phase3a.js` "audit log" case scans recorded
+metadata for anything password-shaped). Viewable at `/admin` → Audit (owner/admin only), latest
+200 events, no pagination UI yet — pilot-scale, not a SIEM.
+
+## 11. API inventory (new/changed)
+
+```
+POST /api/auth/instructor/login       email+password login, rate-limited, no enumeration
+POST /api/auth/logout                 revokes the current instructor session
+GET  /api/auth/session                current instructor identity (role, etc.)
+POST /api/auth/change-password        requires current password; revokes other sessions
+
+POST /api/login                       UNCHANGED route, now backed by persistent sessions
+POST /api/logout                      UNCHANGED route, now CSRF-checked + persistent revoke
+GET  /api/session/whoami              UNCHANGED — Gateway's ownership-check dependency
+
+GET    /api/admin/instructors             owner only
+POST   /api/admin/instructors             owner only
+GET    /api/admin/instructors/:id         owner only — includes session list
+PATCH  /api/admin/instructors/:id         owner only — role/status/name; blocks removing the last active owner
+POST   /api/admin/instructors/:id/revoke-sessions   owner only
+POST   /api/admin/instructors/:id/reset-password    owner only — also revokes that instructor's sessions
+GET    /api/admin/audit-events            admin/owner
+POST   /api/admin/cohorts/:id/instructors owner/admin — assigns an instructor to a cohort
+```
+
+Every pre-existing `/api/admin/*` route from Phase 2B still exists at the same path — behavior
+unchanged for owner/admin, newly scoped for the `instructor` role (see §5/§6). `/api/admin/login`,
+`/api/admin/logout`, `/api/admin/whoami` (the old shared-password routes) are gone — replaced by
+the `/api/auth/instructor/*` routes above.
+
+## 12. Frontend/admin changes
+
+- `AdminPortal.jsx` — email+password login form (was a bare password field); nav now
+  conditionally shows Instructors (owner) and Audit (owner/admin) tabs; adds an Account tab.
+- `InstructorsView.jsx` (new) — create/list/edit instructors, role/status controls, session list
+  + revoke-all, password reset.
+- `AuditView.jsx` (new) — read-only audit event table.
+- `AccountView.jsx` (new) — change-password form for the signed-in instructor.
+- `CohortsView.jsx` — create-cohort form and curriculum-assignment button hidden for the
+  `instructor` role (server already enforces this; this just avoids showing controls that would
+  403).
+- `frontend/src/admin/api.js` / `frontend/src/platform/api.js` — both now read the relevant
+  `rn_csrf_*` cookie and attach `X-CSRF-Token` on every mutating call.
+
+## 13. Security hardening review (what was checked)
+
+- **Cookie settings** — `HttpOnly` on session cookies, `SameSite=Lax`, `Secure` gated behind
+  `COOKIE_SECURE=1` (off by default for local HTTP dev).
+- **CSRF** — §8.
+- **Login brute force** — §9.
+- **Session fixation** — every login issues a brand-new session row (never reuses/upgrades an
+  existing token), so there's nothing to "fix" a pre-auth session into.
+- **Password handling** — §4.
+- **Account enumeration** — identical response for unknown-email and wrong-password (tested).
+- **Authorization bypass** — every `/api/admin/*` route re-checks server-side (§5); tested with
+  both role-based and cohort-scoped negative cases.
+- **Inactive accounts** — rejected at the session-middleware level on every request, not just at
+  login (a deactivation takes effect immediately, §3).
+- **Revoked sessions** — `resolveSession`'s `WHERE revoked_at IS NULL` makes a revoked session
+  fail identically to an expired one.
+- **Role downgrade/upgrade session invalidation** — handled by the live re-fetch design (§3),
+  not a separate revoke pass.
+- **WebSocket authentication** — unchanged from Phase 2A/2B: the Gateway's WS upgrade handler
+  re-verifies ownership via the same session-resolution path as HTTP.
+- **Gateway ownership checks** — unchanged mechanism, tightened cache TTL (5000ms → 2000ms) so a
+  revoked session stops working at the Gateway within a tighter, tested bound.
+- **`trust proxy`** — off by default, opt-in via `TRUST_PROXY=1`, so `req.ip` (used for audit
+  `source_ip` and rate-limit keys) isn't trivially spoofable via `X-Forwarded-For` unless a real
+  trusted proxy is actually in front.
+
+## 14. Test results
+
+- `platform/provisioner/test/run.js` (Phase 1, isolated stack) — **not re-run this phase**: zero
+  source changes to `platform/provisioner/` (confirmed via `git diff`), and its own dev compose
+  stack collides on port 5433 with the shared `platform/docker-compose.dev.yml` stack used for
+  everything else in this phase. Provisioner was still exercised heavily and indirectly through
+  every e2e suite below (provision/reset/destroy, concurrent Prepare Labs, cohort-scoped
+  operations) — all passing.
+- `platform/test/e2e-phase2a.js` — **10/10 passed** (student flow, now under persistent sessions).
+- `platform/test/e2e-phase2b.js` — **12/12 passed** (classroom workflow, now under real
+  instructor accounts instead of a shared password).
+- `platform/test/e2e-phase3a.js` — **21/21 passed**: no-enumeration, CSRF positive+negative,
+  rate limiting, role creation, RBAC denial (instructor→owner-only, instructor→admin-only,
+  admin→owner-only), cohort scoping (visibility + access), last-owner protection, live
+  role/status re-evaluation, password change + old-password rejection + other-session
+  revocation, audit log content (including the no-secrets assertion), student session RBAC,
+  student logout revocation, and session persistence across a real `docker compose restart api`.
+- Real Lab image — rebuilt clean; standalone `--privileged` single-container mode boots and
+  serves with zero Platform API/Postgres/Provisioner dependency (verified live).
+- Frontend production build — clean, no errors.
+- Scenario content / Real Ops bundle / Lab `Dockerfile`/`backend/`/`scripts/` — `git diff`
+  against the Phase 2B milestone SHA is empty for all of them: untouched.
+
+## 15. Known limitations
+
+- **Login rate limiting is in-memory, single-process** (§9) — resets on restart, doesn't share
+  state across multiple Platform API instances. Fine at pilot scale.
+- **Gateway session cache is a 2-second window** — a revoked/expired session can still work at
+  the Gateway for up to ~2s after revocation (tightened from 5s in Phase 2B). Platform API
+  itself always reflects revocation immediately; this bound is specific to the Gateway's
+  whoami-result cache, which exists purely to avoid a Platform API round trip on every single
+  proxied Lab byte.
+- **No distributed session revocation push** — revoking a session updates Postgres immediately;
+  anything holding a *cached* copy of "this session is valid" (only the Gateway does this, and
+  only for 2s) catches up on its next cache miss, not instantly.
+- **Audit log has no pagination UI** — latest 200 events only. Add pagination if usage ever
+  exceeds that being useful.
+- **Roster name-picking is still not strong student identity** (§7) — explicitly documented,
+  not silently glossed over.
+- **`cohort_instructors` role_in_cohort field exists but isn't consulted for finer-grained
+  permissions yet** — currently any assignment grants the full `instructor` role's cohort-scoped
+  actions; a co-teacher vs. lead-teacher distinction within a cohort would consume this field but
+  isn't built.
+- **Exam mode's live bookkeeping is still Lab-local** — unchanged from Phase 2B, still a real gap
+  for anyone relying on cross-restart exam state.
+
+## 16. Future OIDC path
+
+`auth_identities` (§2) already supports it structurally: a Google/OIDC login would create a
+second `auth_identities` row (`provider='google'`, `provider_subject=<their sub>`) pointing at
+an existing `instructor_id`, or create a new `instructors` row + `auth_identities` row for a
+first-time SSO login. The missing piece is the actual OIDC client flow (discovery, token
+exchange, JWT verification) — deliberately **not built this phase**, per the explicit scope
+instruction to stop at a documented adapter interface rather than pull in an OIDC client
+library and expand scope. `instructors.password_hash` staying nullable (already the case) is
+what allows an SSO-only account to exist with no local password at all, whenever that flow is
+built.
+
+## 17. Production HTTPS / cookie expectations
+
+Local dev and the current single-VM pilot deployment run over plain HTTP — `COOKIE_SECURE` is
+unset (cookies lack `Secure`) and `TRUST_PROXY` is unset by default. Before any real-HTTPS
+production deployment: set `COOKIE_SECURE=1` (cookies become HTTPS-only) and, if fronted by a
+reverse proxy/load balancer, set `TRUST_PROXY=1` so `req.ip` reflects the real client IP instead
+of the proxy's.
+
+## 18. BUILT NOW vs. FUTURE
+
+**Built now:** persistent Postgres-backed sessions (student + instructor), per-instructor
+accounts with scrypt password hashing, three-role RBAC enforced server-side, cohort-scoped
+instructor access, CSRF double-submit protection, login rate limiting, platform audit log,
+owner-safety invariant (never zero active owners), password change with other-session
+revocation, `auth_identities` table ready for future OIDC mapping.
+
+**Future (not built):** real OIDC/SSO client flow, multi-instance-safe rate limiting, audit log
+pagination/export, cohort_instructors role-in-cohort permission granularity, distributed
+(non-Gateway-cache) session revocation push, one-time student enrollment codes /
+parent-issued codes, everything already on the Phase 2B "DO NOT BUILD YET" list (capstone
+engine, billing, production Proxmox deployment, etc.) — unchanged, still not in scope.

docs/PHASE3B_LEARNING_AND_ASSESSMENT.md

@@ -0,0 +1,370 @@
+# Phase 3B — Learning & Assessment Engine
+
+Turns the platform infrastructure built in Phases 1–3A (identity, sessions, RBAC, disposable
+Labs, Gateway routing, admin portal) into a real teaching and assessment system: detailed
+attempt telemetry, progressive hints, rule-driven curriculum progression, a proper exam engine,
+a RootNode Capstone, and persistent achievement records. Builds on
+`docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md` — read that first if you haven't.
+
+## 1. What changed, in one paragraph
+
+Phase 2B's `scenario_attempts` table was one row per validation click, written atomically at
+completion, with `hint_count` deliberately left unmeasured. Phase 3B evolves it into a real
+attempt lifecycle — one row per continuous working session on a scenario, with live counters
+(validation attempts/passes/fails, hint reveals, duration) updated in place as the student
+works. On top of that: a rule-driven curriculum-progression engine that actually locks/unlocks
+stages instead of a permanent capstone placeholder; a progressive hint system that's genuinely
+server-enforced (not just collapsed-by-default in the UI); a full exam/capstone assessment
+engine with server-authoritative timers and random scenario draws; and persistent achievement
+records for stage/curriculum/assessment/capstone completion.
+
+## 2. Learning record model
+
+`scenario_attempts` (migration `012`) gained: `cohort_id`, `curriculum_stage` (both snapshotted
+at attempt-start, so a later cohort/curriculum change never rewrites history), `status`
+(`in_progress`/`completed`/`abandoned`), `validation_attempt_count`, `validation_pass_count`,
+`validation_fail_count`, `highest_hint_level`, `duration_seconds`, `assessment_session_id`.
+`result` (Phase 2B) is now nullable — meaningful only once `status = 'completed'`.
+`hint_count` (Phase 2B, always `NULL`) finally gets a `DEFAULT 0` and real increments.
+
+This is an **evolution, not a new table** — Phase 2B's historical rows are backfilled (one
+validation performed, matching their original one-row-per-click semantics), not dropped or
+reshaped. `platform/api/src/attempts.js` owns the lifecycle:
+
+- `getOrCreateOpenAttempt` — finds the open (`in_progress`) attempt for
+  `(student, scenario, environment)`, or starts one. Environment-scoped so a destroyed/recreated
+  Lab never silently resumes an attempt tied to compute that no longer exists.
+- `recordValidation` — increments the attempt/pass/fail counters; closes the attempt
+  (`status='completed'`, `duration_seconds` computed) only on a pass.
+- `recordHintReveal` — sequential only: level *N* can't be revealed before *N-1* has been.
+  Returns a 409 once every hint is exhausted.
+
+No telemetry is invented that the Lab doesn't actually emit — `duration_seconds` is measured
+server-side from `started_at` to completion (not client-reported), and hint reveals only exist
+because Phase 3B builds a real reveal endpoint (§3), not because the old static hint array was
+reinterpreted as "measured."
+
+## 3. Validation telemetry & progressive hints
+
+`POST /api/scenarios/:id/start` — fire-and-forget from the Lab UI when a scenario becomes
+active (both task and MCQ types); creates/reopens the attempt with a real `started_at`.
+
+`POST /api/progress/record` (Gateway-relayed from the Lab's existing validate/answer calls,
+unchanged mechanism from Phase 2A/2B) now routes through `attempts.recordValidation` instead of
+a flat insert, and — on a pass — checks curriculum/capstone/assessment consequences (§4, §6).
+
+`POST /api/scenarios/:id/hint` reveals hints **one at a time, server-enforced**. This required a
+real architectural change: Phase 2B's Lab backend (unmodified, per the "Lab image stays
+unmodified" convention through Phase 3A) returns the scenario's full `hints` array in
+`GET /api/scenarios/:id` — always did, since the Lab has no student/attempt concept at all. A
+client could already see hint 3 in the raw response even with the UI collapsed. Making the gate
+real meant the Gateway now **strips `hints` from that response** (replacing it with a bare
+`hint_count`) for exactly the multi-student, Platform-mediated deployment
+(`platform/gateway/src/server.js`, `GET /lab/:token/api/scenarios/:scenarioId`) — the Lab
+image's own bytes are still untouched; this is a response rewrite at the boundary, the same
+pattern already used for the `hints`-stripping shape as everything else the Gateway mediates.
+Standalone/single-container dev mode never goes through the Gateway, so it keeps the original
+fully-preloaded array unchanged — the frontend detects which mode it's in
+(`scenario.hints === undefined && typeof scenario.hint_count === 'number'`) and switches to
+`ProgressiveHints` (`frontend/src/components/ProgressiveHints.jsx`) only in the gated case.
+
+Instructor-visible attempt summary matches the shape in the Phase 3B spec directly:
+
+```
+Student: Alice   Scenario: Probe Port Mismatch   Attempts: 2
+Validation: Failed 2, Passed 1   Hints used: 1/3   Time: 14m 22s   Final: Completed
+```
+
+— all straight off `scenario_attempts` columns, no derived/estimated numbers, and explicitly
+**not** turned into a score. See §12 for where instructors see this.
+
+## 4. Curriculum completion rules
+
+`scenarios/rootnode-path.json` gained a `version` field and, per stage, a `completion_rule`:
+
+```json
+{ "type": "all_required" }              // every scenario_id in the stage must be completed (default)
+{ "type": "threshold", "percent": 80 }  // at least N% completed
+{ "type": "prerequisites", "scenario_ids": [...] }  // only these specific ids must be completed
+```
+
+The capstone stage is no longer a hardcoded `"locked": true` placeholder — it carries
+`"type": "capstone"`, an `"unlock_rule"` (`{"type":"stages_complete","stage_ids":[...]}`), and a
+`"capstone_assessment_id"` pointing at the assessment definition that drives it (§6/§7).
+
+`platform/api/src/curriculum-rules.js`'s `computeCurriculumState(path, progress, capstoneStatus)`
+is the rule engine — pure, synchronous, no DB access — answering: per-stage locked/complete/
+percent/next-scenario, the student's current stage, overall percent complete, and the capstone's
+unlock status (server route supplies `capstoneStatus` after checking for a
+`capstone_completed` achievement, since that's Postgres state this module doesn't touch).
+Exposed at `GET /api/curriculum/state` (new; `GET /api/curriculum/path` from Phase 2A/2B is
+unchanged and still used by the pre-existing dashboard summary).
+
+Stage/curriculum completion also triggers achievement recording (§8) automatically, from inside
+`POST /api/progress/record` — no separate "check for completion" step the student or frontend
+has to remember to call.
+
+## 5 & 6. Assessment model and exam engine
+
+`PRACTICE` is just... practice: the existing curriculum flow, hints freely available (subject to
+the scenario actually having any), unrestricted retries, no timer, no session concept.
+
+`ASSESSMENT` (exam or capstone — same underlying engine, §7 covers what makes a capstone
+different) is a **definition** (the reusable template: pool, duration, hint policy, completion
+rule) producing **sessions** (one per student attempt, immutable snapshot of what was drawn and
+under what rules). New tables (migration `013`):
+
+```
+assessment_definitions          slug PK, type ('exam'|'capstone'), title, duration_minutes,
+                                 hint_policy ('free'|'disabled'|'flagged'), pool_spec JSONB,
+                                 completion_rule JSONB, unlock_rule JSONB (capstone only),
+                                 version INTEGER, status ('active'|'inactive')
+assessment_cohort_assignments   which cohorts a definition is available to
+assessment_sessions             one per student attempt — snapshots type/title/duration_minutes/
+                                 hint_policy from the definition at draw time, plus
+                                 definition_version, started_at, server-computed expires_at,
+                                 submitted_at, random_seed, result JSONB
+assessment_session_scenarios    the drawn set, ordered, with per-scenario status + a real FK
+                                 back to the scenario_attempts row once worked
+```
+
+`exam_sessions` (Phase 1/2B, historical-import-only from the old Lab-local SQLite exam
+bookkeeping) is **left untouched** — it was already scoped as dead historical data, never the
+live mechanism, so there was nothing to migrate into the tables above without inventing data
+that was never real. This is a deliberate non-duplication: the assessment tables above *are*
+the real thing Phase 2B's note said didn't exist yet.
+
+`pool_spec` shape:
+
+```json
+{ "required": ["scenario-id", ...], "random": [{ "count": 1, "from": ["a", "b", "c"] }, ...] }
+```
+
+`platform/api/src/assessments.js`'s `drawScenarios` includes every `required` id, plus `count`
+random picks from each `random` group, shuffled together into presentation order. The draw uses
+a tiny deterministic PRNG (mulberry32, seeded from `crypto.randomBytes` — no new dependency)
+purely so the seed can be recorded for audit; a student never sees the seed or the undrawn pool
+before starting.
+
+**One assessment at a time per student** — `startSession` refuses if the student already has a
+`not_started`/`in_progress` session for *any* definition. This keeps "which scenario is this
+validate call happening inside" unambiguous for hint-policy enforcement (§19) without needing
+the client to declare a mode.
+
+**Timer**: `expires_at` is computed once, server-side, at `started_at + duration_minutes`, and
+never recomputed from anything the client sends. Expiry is checked **lazily** — whenever a
+session is read or written, if `now() > expires_at` and it's still `in_progress`, it flips to
+`expired` right then. No background cron (explicitly out of scope this phase — see the
+non-goals list). Verified live: a 1-minute test definition correctly transitioned to `expired`
+on the first request after the minute passed, and unblocked starting a new assessment.
+
+## 7. RootNode Capstone
+
+A capstone is an `assessment_definitions` row with `type='capstone'` — same engine as an exam,
+different framing and unlock gate. The shipped default (seeded in migration `013`, idempotent
+`INSERT ... ON CONFLICT DO NOTHING`) is `rootnode-capstone`:
+
+- **Required** (always drawn): all four RootNode Real Ops scenarios
+  (`rootnode-runaway-monitor`, `broken-deployment`, `rootnode-probe-port-mismatch`,
+  `rootnode-enforce-limits`) — "feature prominently," per the spec, satisfied by making them
+  non-optional rather than just likely.
+- **Random**: one Workloads task, one Configuration task, one Troubleshooting task — task-type
+  scenarios preferred over MCQ, since the point is operational ability, not recall.
+- 90 minutes, `hint_policy: 'flagged'` (available, but every use is recorded — appropriate for
+  a capstone that should mostly reflect independent work without being punitive about needing a
+  nudge).
+- `unlock_rule`: every non-capstone curriculum stage complete (Foundation through Real Ops).
+
+`GET /api/capstone` is a student-friendly view combining `computeCurriculumState`'s capstone
+block with the definition and the student's own session history —
+`locked` → `unlocked` → `completed`, with a prerequisite checklist while locked. Verified live,
+end to end: locked with all six blocking stage ids, unlocked to zero blocking ids the moment the
+last stage completed, a real draw (7 scenarios, all four Real Ops present), completion of all
+seven finalizing the session and recording a `capstone_completed` achievement.
+
+## 8. Achievement / completion records
+
+`achievements` (migration `014`): `student_id`, `achievement_type`
+(`stage_completed`/`curriculum_completed`/`assessment_completed`/`capstone_completed`),
+`curriculum_path_id`/`curriculum_version` (for stage/curriculum types),
+`assessment_session_id` (for assessment/capstone types), `achieved_at`, `metadata`.
+
+`recordAchievement` is idempotent via a `WHERE NOT EXISTS` guard (not a unique-index/
+`ON CONFLICT` dance — simple and correct at this write volume) — calling it again for something
+already recorded is a safe no-op. Triggered automatically: `checkStageAndCurriculumAchievements`
+runs inside `POST /api/progress/record` after every pass; `recordAssessmentAchievement` runs
+after `assessments.recordScenarioOutcome`/`submitSession` finalizes a session, and only on an
+actual pass (defensive — today's only `completion_rule` is `all_scenarios_passed`, which already
+guarantees a `completed` session passed, but a future threshold-based rule shouldn't silently
+grant achievements for a partial result).
+
+**Not a certificate.** No public/shareable artifact is generated — this is explicitly a Phase
+4/5 concern (see the non-goals list); a certificate can be rendered from these records later
+without needing new data.
+
+## 9. Assessment/exam Lab behavior
+
+An assessment doesn't provision a separate Lab — the student works through their drawn
+scenarios inside the **same** disposable environment their curriculum work already uses. This
+is what makes "Lab reset doesn't erase assessment state" nearly free: assessment state
+(`assessment_sessions`, `assessment_session_scenarios`, `scenario_attempts`) lives entirely in
+Platform Postgres; the Lab environment is purely compute. Resetting/recreating it changes the
+container, never the rows. Verified live: reset an environment mid-assessment,
+`expires_at`/`status` on the session were unchanged afterward.
+
+**Assessment-mode detection is entirely server-derived** — `findActiveAssessmentContextForScenario`
+looks up whether the scenario a `validate`/`hint` call is happening against is currently in the
+student's own active session's drawn set. Nothing the client sends declares "I'm in assessment
+mode"; the server's own `assessment_session_scenarios` table is the only source of truth (see
+§19).
+
+If Lab infrastructure fails mid-assessment, the assessment session itself is unaffected — an
+instructor can reset (or, if truly needed, destroy/reprovision) the student's Lab via the
+existing admin environment controls (Phase 2B) without touching assessment state at all; there
+is no code path that resets an assessment as a side effect of a Lab operation.
+
+## 10 & 11. Student UI and Lab UX
+
+`frontend/src/platform/StudentDashboard.jsx` is now tabbed: **My Learning** (the original
+Phase 2A/2B "Up Next" + Launch/Reset Lab flow, extracted unchanged into `MyLearningTab.jsx` and
+extended with an overall percent-complete bar from the new rule-driven curriculum state),
+**Practice** (scenario/stage status + recent attempt history), **Assessments** (available/
+active-with-live-countdown/history), **Capstone** (locked checklist → unlocked → start/resume →
+completed, with attempt history), **Achievements** (a flat, dated list — not a leaderboard).
+
+Inside the Lab UI itself (`frontend/src/components/ScenarioPanel.jsx`, `App.jsx`):
+`ProgressiveHints` replaces the static hint array render when the Gateway has stripped hints
+(§3); an `AssessmentBanner` (new, top-level, polls `/api/assessments/active`) shows a live
+countdown and per-scenario completion count whenever an assessment is running — distinct from,
+and rendered alongside, the pre-existing Lab-local exam-mode UI (`ExamTimer`/`ExamSession` etc.,
+upstream KubeKosh feature, untouched). Both render nothing in standalone/single-container dev
+mode (no Platform API to poll there), so neither regresses that deployment path.
+
+## 12. Instructor learning analytics
+
+`/admin` → **Learning**: cohort summary (student count, 7-day active-learner count, average
+completion, per-stage completion counts), a **Needs Attention** list, and a per-student
+drill-down (curriculum state, full attempt history with validation/hint counts, assessment
+history). `/admin` → **Assessments**: create/edit definitions (admin/owner), assign to a cohort,
+view/cancel sessions — visible to every instructor role, cohort-scoped server-side for the plain
+`instructor` role the same way Phase 3A's other cohort-scoped routes are.
+
+`GET /api/admin/scenario-analytics` (optional `?cohort_id=`): completions, distinct students,
+average validation attempts, total failures, total hints used, average completion time — one
+`GROUP BY scenario_id` query over `scenario_attempts`, nothing pre-aggregated or cached.
+
+## 13. "Needs Attention"
+
+`GET /api/admin/cohorts/:id/needs-attention` computes four signals per student, on read (no
+stored table, no background job): **Repeated Attempts** (an open attempt with ≥3 failed
+validations), **May Need Help** (an open attempt where a hint has been used but the scenario
+isn't done), **Needs Attention — inactive** (no activity in 7 days), and **Needs Attention —
+incomplete assessment** (their most recent assessment session expired without completing). All
+four thresholds are named constants in `admin-learning-routes.js`
+(`NEEDS_ATTENTION_FAIL_THRESHOLD`, `NEEDS_ATTENTION_STALE_DAYS`), not hardcoded inline. Wording
+is deliberately instructional (`Needs Attention`, `May Need Help`, `Repeated Attempts`) — an
+explicit test asserts none of the returned labels match punitive language.
+
+## 14 & 15. Assessment/capstone management (admin)
+
+A structured form (`frontend/src/admin/AssessmentsView.jsx`) — id, title, type, duration, hint
+policy, and a raw JSON `pool_spec` textarea. Not a drag-and-drop authoring tool, per the explicit
+scope line; the JSON textarea is honest about what's actually being edited rather than hiding it
+behind partial UI that can't express every pool shape. Editing a definition's
+duration/hint_policy/pool_spec/completion_rule bumps its `version` automatically
+(`admin-learning-routes.js` diffs the incoming fields against the current row) — cosmetic edits
+(title, description) don't. Create/edit is admin/owner only server-side; assign-to-cohort and
+session view/cancel are available to a scoped `instructor` too, matching the RBAC matrix (§18).
+
+## 16. Versioning
+
+Deliberately minimal, per the explicit "don't overbuild full CMS versioning" instruction:
+
+- **Curriculum path**: a plain `"version": 1` integer in `rootnode-path.json` itself, recorded
+  on `stage_completed`/`curriculum_completed` achievements as a snapshot.
+- **Assessment definitions**: a plain incrementing `version` integer, bumped only on a semantic
+  change (duration/hint_policy/pool_spec/completion_rule — anything that would change what a
+  session is graded against). `assessment_sessions.definition_version` snapshots which version
+  was live at draw time, alongside a full redundant snapshot of the fields themselves
+  (title/duration/hint_policy) — so a later definition edit, or even deletion, can never change
+  what an already-started session is measured against.
+
+No full version-history table exists for either — if that's ever needed, `version` is already a
+column to build on, not a retrofit.
+
+## 17. RBAC matrix (Phase 3B additions)
+
+| Action | owner | admin | instructor | student |
+|---|---|---|---|---|
+| Create/edit assessment definitions | ✅ | ✅ | ❌ | ❌ |
+| Assign an assessment to a cohort | ✅ | ✅ | ✅ (own cohorts) | ❌ |
+| View/cancel assessment sessions | ✅ (any) | ✅ (any) | ✅ (own cohorts) | ❌ |
+| View cohort learning summary / needs-attention / scenario analytics | ✅ (global) | ✅ (global) | ✅ (own cohorts) | ❌ |
+| View a student's learning detail | ✅ | ✅ | ✅ (if enrolled in an owned cohort) | own only |
+| Start/work an assessment, view own attempts/hints/achievements | ❌ | ❌ | ❌ | ✅ (own only) |
+
+Enforced entirely server-side, reusing Phase 3A's `rbac.js` (`requireAdminOrOwner`,
+`requireAnyInstructor`, `requireCohortAccess`, `requireStudentCohortAccess`) — no new
+authorization primitives were needed, only new routes wired through the existing ones.
+
+## 18. Security / integrity
+
+- **Timer is server-authoritative** (§6) — `expires_at` fixed at draw time, never accepts a
+  client value, checked lazily on every touch.
+- **Scenario draw is server-stored** — `assessment_session_scenarios` is the only source of
+  truth for what a student is supposed to be working on; nothing the client sends can add,
+  remove, or reorder it.
+- **A student cannot submit/read another student's session** — every assessment route filters
+  by `student_id = req.studentId` server-side; a foreign session id returns 404, not 403 (same
+  "don't confirm existence" posture as Phase 3A's RBAC denials) — verified by an explicit test.
+- **Gateway ownership** (Phase 2A/2B/3A) is unchanged and still enforced on every proxied Lab
+  request, HTTP and WebSocket, including the new `/start` and `/hint` relays.
+- **Lab recreation never resets attempt/exam state** (§9) — verified live.
+- **Hidden solution/pool data**: undrawn pool alternatives are never returned to the student
+  (only the actual draw); hints beyond the currently-unlocked level are never sent (§3, the
+  actual mechanism, not just a UI convention).
+- **No invasive anti-cheat** — no browser surveillance, no lockdown mode. Explicitly out of
+  scope, per the non-goals list.
+
+## 19. Dev/test commands
+
+```bash
+cd platform && docker compose -f docker-compose.dev.yml up -d
+(cd api && PLATFORM_DB_URL=postgres://postgres:postgres@localhost:5433/rootnode_platform \
+  node bootstrap-owner.js [email protected] "Your Name" "a-real-password-12-chars-plus")
+
+OWNER_EMAIL=[email protected] OWNER_PASSWORD=... node test/e2e-phase2a.js
+OWNER_EMAIL=[email protected] OWNER_PASSWORD=... node test/e2e-phase2b.js
+OWNER_EMAIL=[email protected] OWNER_PASSWORD=... node test/e2e-phase3a.js
+OWNER_EMAIL=[email protected] OWNER_PASSWORD=... node test/e2e-phase3b.js
+```
+
+`e2e-phase3b.js` additionally shells out to `docker compose restart api` for its restart-
+persistence case (set `SKIP_RESTART_TEST=1` to skip that one case if running somewhere that
+isn't safe to restart).
+
+## 20. Known limitations
+
+- **No automatic "abandoned" detection** — an attempt a student never returns to stays
+  `in_progress` forever; there's no reaper tying Lab destruction back to attempt state. A
+  documented, deliberate scope line (would need wiring to Provisioner `environment_events`,
+  more machinery than the instructional-visibility goal needs).
+- **`cohort_instructors.role_in_cohort`** (Phase 3A) still isn't consulted for finer-grained
+  assessment permissions — any cohort assignment grants the full scoped-instructor action set.
+- **Needs-attention thresholds are fixed constants**, not per-cohort configurable yet.
+- **No pagination** on the audit log (Phase 3A limitation, unchanged) or on scenario analytics.
+- **Assessment pool_spec authoring is raw JSON** in the admin UI — correct and complete, but not
+  a guided form; a validation-assist UI is a natural but unbuilt next step.
+- **One assessment at a time per student** — intentional (§6), but means a student can't have a
+  capstone and an exam "in flight" simultaneously even if that were ever desired.
+
+## 21. Phase 4 boundary
+
+Everything in this document runs on a single dev machine against
+`platform/docker-compose.dev.yml`. **Not built, and explicitly out of scope this phase:**
+production Hetzner/Proxmox deployment, production OIDC provider integration, a parent portal,
+payments, public signup, automated email, equipment inventory, a multi-host scheduler,
+Grafana/Prometheus production dashboards, public certificates, a marketplace/self-paced commerce
+layer, the six held KubeKosh scenarios, invasive proctoring, and AI-driven grading. All of that
+stays exactly where the Phase 3A doc's non-goals list and this document's §21 leave it — Phase 4
+territory.

docs/PHASE4_1_PREPRODUCTION_HARDENING.md

@@ -0,0 +1,254 @@
+# Phase 4.1 — Pre-Production Hardening
+
+**Status: PHASE 4.1 COMPLETE. PRE-PRODUCTION HARDENING COMPLETE. READY FOR HARDWARE DEPLOYMENT.**
+
+Phase 4 built the production infrastructure package with the real Hetzner/Proxmox hardware not
+yet purchased, and flagged one genuine architectural gap: the Gateway's mechanism for reaching
+a student Lab assumed Gateway and Lab shared a Docker daemon, which is false the moment Labs run
+on a genuinely separate `rn-lab-host-01` VM. Phase 4.1's job was to close that gap and harden
+everything else discovered along the way, still without the real hardware.
+
+## 1. The core fix: a Lab Host Router
+
+**Before:** Gateway → `http://${env.internal_ip}:${env.internal_port}` directly — a Docker
+bridge-local address, unreachable across a real VM boundary.
+
+**After:** Gateway → (mode-aware) → either `direct` (unchanged, dev/single-host) or `router`
+(production): a small new service, `platform/lab-router/`, runs on the Lab Host itself,
+authenticates the Gateway via mTLS (the same private CA the Docker TLS control plane already
+used, extended with two new leaf certs), resolves an opaque routing token to a local container
+purely from `docker ps` label state (no Postgres access, no call back to the Provisioner), and
+reverse-proxies HTTP and WebSocket traffic to it.
+
+The decision of which mode a given `lab_host` uses is data-driven
+(`lab_hosts.routing_mode`/`router_endpoint`, `platform/provisioner/migrations/004_lab_hosts_routing.sql`),
+resolved once per request in `platform/gateway/src/lab-endpoint.js`'s `labTarget()` — the only
+place in the Gateway that knows this distinction exists. Every proxy/fetch call site in
+`platform/gateway/src/server.js` goes through it.
+
+**Exact `env.internal_ip` replacement:** `labTarget(env, token)` returns `{ url, headers, agent,
+mode }`. In `direct` mode, `url` is exactly the old `http://internal_ip:internal_port`. In
+`router` mode, `url` is the lab_host's `router_endpoint`, `headers` carries
+`X-RootNode-Route-Token: <token>` (computed server-side from the Provisioner-verified
+environment row — never trusted from the browser), and `agent` is an `https.Agent` configured
+with the Gateway's mTLS client identity.
+
+## 2. No per-student host port
+
+Deliberately not solved by publishing a host port per Lab (the originally-flagged, rejected
+approach). The Router resolves entirely from Docker's own label state on its own host — no
+port-per-student anything, no dynamic firewall rule per Lab.
+
+## 3. Lab Host Router — design
+
+See `platform/lab-router/src/server.js`'s header comment for the full "narrow by design" list:
+one route (proxy-by-token), requires mTLS (no bearer-token fallback), never exposes Docker API/
+container IDs/network info to its caller, never provides student-to-student routing (each
+request resolves to exactly the one container matching its own token).
+
+## 4. Multi-Lab-Host ready
+
+Routing is resolved per `lab_host_id` — adding `rn-lab-host-02` later is one new `lab_hosts` row
+(its own `routing_mode`/`router_endpoint`/TLS material), no Gateway code change. No scheduler
+was built (explicitly out of scope) — the Provisioner still picks "the one enabled lab_host"
+(`selectLabHost`), unchanged from Phase 1.
+
+## 5. Local development compatibility
+
+`dev-local` (the Unix-socket lab_host used by `docker-compose.dev.yml`) stays `routing_mode:
+direct` — zero behavior change for the T480/any local dev setup, confirmed by the full existing
+regression suite passing unmodified (§29 below) and by every new drill in this phase running
+against the same dev stack. The standalone single-container Lab image build/boot is unaffected
+(it never touches the Gateway or Provisioner at all).
+
+## 6-9. Simulation, HTTP/WS validation, security tests, routing token security
+
+`infra/scripts/simulate-two-host/` — a real two-Docker-network simulation (not mocks): Gateway
+attached ONLY to an isolated bridge with no route to any Lab's bridge network, Lab Host Router
+host-networked (mirrors `egress-proxy`'s existing pattern) so it can reach whatever per-Lab
+bridge the Provisioner creates. 13/13 real assertions pass, including:
+
+- Gateway genuinely cannot open a TCP connection to a Lab's Docker-internal IP (proven from
+  inside the Gateway container's own network namespace via a raw connect attempt).
+- Gateway reaches the Lab correctly through the Router — HTTP AND a real WebSocket terminal
+  session running a genuine `kubectl get nodes` inside the Lab.
+- Alice/Bob isolation (own lab ALLOW, other's DENY — HTTP and WebSocket both), garbage tokens,
+  anonymous requests, and destroyed-environment tokens are all rejected through the real code
+  path.
+- The Router refuses any connection with no client certificate — mTLS is the real
+  authentication mechanism.
+
+Routing token security reviewed: already CSPRNG since Phase 1 (`generateRoutingToken`), never
+logged in plaintext (the Router's `tokenFingerprint` truncates), redacted in every API response
+except the two narrow internal reads that legitimately need it, and — critically — the header
+the Router trusts is computed server-side from the Provisioner-verified environment row, never
+read from the browser's own request, so a browser cannot forge routing by supplying its own
+`X-RootNode-Route-Token`.
+
+## 10. Control plane vs data plane
+
+Kept strictly separate — see `docs/PRODUCTION_NETWORK_SECURITY.md`'s dedicated section. Student
+browser traffic is never proxied through the Docker API at any point.
+
+## 11. Firewall update
+
+`infra/firewall/rn-lab-host-01.rules`'s old speculative wide port-range allowance replaced with
+one narrow rule: `platform_ip` → the Router's port only (`8443` default, configurable).
+
+## 12. Self-paced / remote delivery architecture check
+
+`docs/REMOTE_AND_SELF_PACED_ARCHITECTURE.md`. Short version: student-driven provisioning,
+cohort-less students, and "idle reaper destroys → progress survives → student returns → fresh
+Lab → curriculum continues" all already worked before this phase and are now proven end-to-end
+by two new drills. The one real gap for actual remote/self-paced delivery is student
+authentication (today's bare `student_id` login assumes an instructor-controlled roster) — not
+built here, explicitly Phase 5 scope.
+
+## 13. Abandoned attempt cleanup
+
+`scenario_attempts.status = 'abandoned'` (already a valid value since Phase 3B, never
+previously set) now gets set on: environment destroy/reset (student- or instructor-triggered),
+logout, session expiry (piggybacked on the existing hourly session sweeper — no new background
+job), and switching to a different scenario while one is still open. Never a punitive marker —
+`result` stays NULL, history is preserved, instructors see an honest "abandoned (reason)"
+instead of a phantom "still in progress."
+
+## 14. Gateway session cache
+
+Reviewed — already a tight 2-second TTL since Phase 3A, specifically to bound the
+revocation-propagation window. Decision: **keep it, don't add push-based invalidation** — the
+added coupling (Platform API would need to know how to reach the Gateway) isn't justified by
+shrinking an already-2-second window further. Documented reasoning, not a silently-accepted gap.
+
+## 15. Rate limiting
+
+Login rate limiting moved from an in-memory `Map` (reset on every restart, not shareable across
+instances) to Postgres (`login_attempts` table, `migrations/016_login_attempts.sql`) —
+`platform/api/src/security.js`'s `tooManyAttempts()`. No Redis added. Restart behavior
+confirmed for real: `platform/test/e2e-phase3a.js`'s rate-limiting test passes after a genuine
+Platform API restart in the same run.
+
+## 16. Pagination
+
+Real server-side pagination (`platform/api/src/pagination.js`) on: the audit log (was a flat
+`LIMIT 200`), student attempt history (was `LIMIT 100`), and assessment session history (was
+**fully unbounded** — the one genuine growth risk found). Scenario analytics was deliberately
+left as-is — grouped by scenario id, naturally bounded around ~100 rows, no real growth risk to
+paginate against. Frontend (`AuditView.jsx`, `AssessmentsView.jsx`, `StudentsView.jsx`) updated
+to match; `frontend` build confirmed clean.
+
+## 17. Needs-attention configuration
+
+`NEEDS_ATTENTION_FAIL_THRESHOLD`/`NEEDS_ATTENTION_STALE_DAYS` moved from hardcoded constants to
+env-var-configurable (matching the existing session-TTL pattern), sensible defaults unchanged.
+
+## 18. Assessment authoring UX
+
+Raw-JSON `pool_spec` textarea replaced with a structured editor
+(`frontend/src/admin/AssessmentsView.jsx`'s `PoolSpecEditor`): required scenarios and random
+pools picked from a real scenario catalog (`GET /api/admin/scenario-catalog`, new), grouped by
+curriculum stage, via native multi-select — no new UI framework. An owner-only "advanced" raw
+JSON view remains for anything the structured editor doesn't cover.
+
+## 19. Cohort role-in-cohort
+
+`cohort_instructors.role_in_cohort` existed since Phase 2B but was never read. Implemented
+minimally: `teacher` (unchanged full capability) vs `viewer` (read-only — dashboards/analytics
+still visible, but Prepare/Destroy Labs and provisioning a student's environment are now 403'd
+server-side, `rbac.js`'s `requireCohortWriteAccess`/`requireStudentCohortWriteAccess`).
+
+## 20. Backup / restore destructive drill
+
+`infra/backup/test-destructive-restore-drill.sh` — real owner/admin/cohort/3-students/progress/
+attempts/assessment/achievements seeded through the real Platform API, encrypted-backed-up, the
+disposable Postgres container **genuinely destroyed** (not just restored into a second
+container), a fresh Postgres created from nothing, restored, and the real Platform API booted
+again against the restored database and used to log in as the restored admin over HTTP. All
+data verified present; never touches the developer's real database.
+
+## 21. Lab Host rebuild drill
+
+`infra/scripts/drills/test-lab-host-loss.js` — a student's Lab container is destroyed out from
+under the Provisioner (no clean destroy call, simulating total Lab Host loss). Proves: Platform
+stays up throughout, the stale environment is never presented as healthy once the Provisioner's
+real `reconcileOnStartup` reconciliation runs, academic progress is untouched, and the student
+can launch a genuinely new Lab and continue.
+
+## 22. Deployment rollback test
+
+`infra/scripts/drills/test-deployment-rollback.sh` — builds a known-good and a deliberately
+broken gateway image, "deploys" each via the real deterministic-tag mechanism, proves the smoke
+test catches the regression, computes the rollback target with the exact same
+`deploy-history.log` logic `rollback-production.sh` uses, and proves the rollback recovers.
+Documents explicitly that image rollback never implies a DB migration rollback.
+
+## 23. CI/CD failure tests
+
+`infra/scripts/drills/test-ci-fails-closed.sh` — proves all six required failure modes (test/
+syntax failure, frontend build failure, image build failure, config validation failure,
+migration preflight failure, staging smoke test failure) genuinely exit nonzero. **Found and
+fixed two real pre-existing bugs**: `staging-smoke-test.sh` and `production-smoke-test.sh` both
+had a classic `set -e` gotcha (`curl ... && echo "OK"` as one statement — a failing command
+that isn't the last in an `&&` chain doesn't trigger `-e`) that let an unreachable/broken
+endpoint fall through silently instead of failing the smoke test. Fixed in both files.
+
+## 24. Security scanning
+
+`infra/ci/gitea-workflows/build-and-test.yml`'s new `security-scan` job — npm audit, gitleaks
+(secrets), hadolint (Dockerfiles), shellcheck (shell scripts), trivy (container image CVEs).
+All free/open-source. Severity policy documented in `docs/SECURITY_SCANNING.md`: CRITICAL/HIGH
+blocks the build, MEDIUM/LOW is reported only. `security-scan` gates `build-images` the same
+way `regression` does.
+
+## 25. Version / release visibility
+
+`GET /api/version` (Platform API) — app version (`package.json`), deployed Git SHA
+(`GIT_SHA` env var, set to the same value as the image tag in the production compose file), and
+the most recently applied migration as a schema-version stand-in. Unauthenticated, minimal, no
+infrastructure detail.
+
+## 26. Admission control failure mode
+
+`resource-policy.yaml`'s new (disabled-by-default) `admission_control.max_concurrent_labs` —
+when set, the Provisioner checks it BEFORE touching Docker at all, so a full host fails cleanly
+(503, `CAPACITY_EXCEEDED`) instead of failing mid-provision. Relayed by the Platform API as a
+clean "Lab capacity is temporarily full. Try again shortly." — never a raw 500. A new
+`GET /capacity` Provisioner endpoint feeds the instructor dashboard's capacity display.
+
+## 27. Fake cohort dress rehearsal
+
+`infra/scripts/drills/test-fake-cohort-rehearsal.js` — one continuous narrative: instructor
+login, cohort + 4 students, curriculum assignment, Prepare Labs, students working different
+scenarios, hints, a deliberate failed validation, instructor analytics, a Lab reset, a Lab
+reaped (same consequence as the real idle reaper — see the drill's own comment on why the real
+multi-minute timer isn't waited out), the student returning and continuing, an exam
+assigned/taken, and end-of-class Lab destruction — progress verified intact after every
+destructive step. 14/14 passing.
+
+## 28. Documentation
+
+This file, `docs/REMOTE_AND_SELF_PACED_ARCHITECTURE.md`, `docs/SECURITY_SCANNING.md` (new).
+Updated: `docs/LAB_ARCHITECTURE.md`, `docs/PRODUCTION_NETWORK_SECURITY.md`,
+`docs/PRODUCTION_DEPLOYMENT.md`, `docs/PRODUCTION_VALIDATION_CHECKLIST.md`, `docs/BACKUP_DR.md`,
+`docs/ENGINEERING_SOP.md`, `README.md`, `platform/README.md`.
+
+## 29. Regression
+
+Re-ran the full existing suite after every application-code change in this phase:
+`e2e-phase2a.js` (10/10), `e2e-phase2b.js` (12/12), `e2e-phase3a.js` (21/21 — including a real
+audit-log pagination-shape fix and confirming rate-limit persistence across a genuine restart),
+`e2e-phase3b.js` (24/24). Frontend production build clean. Real Lab image builds/boots (both
+dev-compose and standalone single-container). `tofu validate`, `ansible-playbook
+--syntax-check`, production Compose config (both platform and lab-host), `caddy validate`,
+`promtool`/`amtool`, and the backup/restore mechanism all re-validated clean after the
+infrastructure changes in this phase (new `lab-router` service, new firewall rule, new Ansible
+tasks). No knowingly-unexplained regression was left in this codebase at the end of this phase.
+
+## What Phase 4.1 deliberately did NOT build
+
+Production deployment itself, Hetzner/Proxmox installation, public course signup, payments,
+subscriptions, parent portal, marketing site, full LMS, video hosting, email automation,
+certificates, course marketplace, mobile app, a multi-host scheduler, an AI tutor, invasive
+proctoring, held scenario content, student email/password authentication (documented as the one
+real gap for self-paced delivery, not built). All explicit non-goals per this phase's
+authorization.

docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md

@@ -0,0 +1,187 @@
+# Phase 4 — Production Infrastructure Package
+
+**Status: PHASE 4 BUILD COMPLETE. PRODUCTION DEPLOYMENT PENDING HARDWARE.**
+
+The dedicated Hetzner server this is designed for hasn't been purchased yet. Everything in this
+document and the `infra/` tree it describes is buildable, testable (against local
+Docker/Postgres/disposable certs), and reviewable **now** — none of it requires the real
+hardware to exist. What genuinely can't happen until the hardware exists is called out
+explicitly throughout, never silently assumed to already work.
+
+This document is the map. Detail docs: `docs/PRODUCTION_DEPLOYMENT.md` (step-by-step),
+`docs/PRODUCTION_NETWORK_SECURITY.md` (network/firewall/TLS design), `docs/BACKUP_DR.md`
+(backup/restore/disaster recovery), `docs/OBSERVABILITY.md` (metrics/logs/alerts),
+`docs/CAPACITY_PLANNING.md` (sizing model), and the `docs/RUNBOOK_*.md` files (14 topics,
+command-oriented).
+
+## 1. What was built
+
+```
+infra/
+├── proxmox/          manual bare-metal install docs + cloud-init template definition
+├── terraform/         VM creation (rn-platform-01, rn-lab-host-01) — real `tofu validate` pass
+├── ansible/            all host configuration — real `ansible-playbook --syntax-check` pass
+│   ├── roles/          common, firewall, docker-tls, platform, lab-host, monitoring-agent, backup
+│   ├── group_vars/     production.yml, staging.yml, vault template
+│   └── site.yml        top-level playbook, correct role ordering
+├── docker/            production Compose files, Caddyfile, Postgres tuning — real `docker
+│                       compose config` + `caddy validate` pass
+├── firewall/           iptables-restore rulesets for all 3 hosts — structural lint pass
+├── monitoring/          Prometheus/Alertmanager/Loki/Promtail/Grafana config — real `promtool`
+│                        + `amtool` validation pass
+├── backup/              Postgres backup/restore/verify scripts — REAL end-to-end test against
+│                        disposable local Postgres, including the actual production migrations
+├── scripts/             deploy/rollback/smoke-test/CI/loadtest/capacity-model tooling
+├── ci/                  Gitea Actions workflow (build/test/stage automatic, prod manual)
+└── environments/        dev/staging/production config templates, no secrets committed
+```
+
+18 new docs (this file + 5 detail docs + 12 runbooks), 4 updated (`LAB_ARCHITECTURE.md`,
+`ENGINEERING_SOP.md`, `README.md`, `platform/README.md`).
+
+## 2. Architecture (unchanged from the design, now codified)
+
+```
+Hetzner Dedicated Server
+└── Proxmox VE
+    ├── rn-platform-01   (frontend, Platform API, Gateway, Provisioner, Postgres,
+    │                      Prometheus/Alertmanager/Grafana/Loki, backup cron, Caddy)
+    └── rn-lab-host-01   (Docker Engine w/ TLS, egress proxy, disposable student Labs,
+                           node-exporter/cadvisor/promtail)
+```
+
+The Platform VM / Lab Host VM security boundary from `docs/LAB_ARCHITECTURE.md` is the one
+thing this phase was explicitly told never to weaken — it's codified, not just described, in
+`infra/firewall/` and `infra/ansible/roles/docker-tls/`.
+
+## 3. VM specifications
+
+| | rn-platform-01 | rn-lab-host-01 |
+|---|---|---|
+| Baseline (default in `infra/terraform/variables.tf`) | 4 cores, 16 GB RAM, 100 GB disk | 24 cores, 96 GB RAM, 500 GB disk |
+| Recommended (once real host is ~16c/32t/128GB) | same — Postgres/API/Gateway/Provisioner don't need much | majority of remaining host resources |
+| Max-growth | scale RAM with Postgres `shared_buffers` if instructor/cohort count grows a lot | scale with measured concurrent-Lab capacity (`docs/CAPACITY_PLANNING.md`) |
+| Configurable via | `terraform.tfvars`' `platform_vm`/`lab_host_vm` objects | same |
+
+NUMA/CPU pinning: not configured — not useful at this scale (a handful of VMs on one physical
+host, not a dozen contending for cache locality). Revisit only if real load testing shows a
+reason to.
+
+## 4. Storage decision framework
+
+Not a final answer — `infra/environments/production/provisioner-config/README.md` and this
+section exist so the final ZFS layout is a deployment-time decision made against real disks,
+not guessed now. Candidate layouts (`infra/terraform/variables.tf`'s `vm_disk_datastore` names
+whichever one gets chosen):
+
+- **4× NVMe**: mirrored vdevs (RAID10-equivalent) — two mirror pairs, one for
+  Postgres/platform data (I/O-sensitive, small), one for Lab Host disposable data
+  (throughput-sensitive, large, never needs redundancy since nothing on it is precious).
+- **2× SSD/NVMe**: one mirrored vdev, logical dataset separation (ZFS datasets, not separate
+  pools) between platform (`{{ rootnode_data_root }}/postgres`, `/backups`) and Lab Host data.
+- **Mixed SSD/HDD**: only if the purchased server's actual disks require it — HDD for
+  disposable Lab scratch space is acceptable (it's disposable), never for Postgres.
+
+**Never single-disk for Postgres data**, in any layout — a mirror is the floor, not a nice-to-have.
+
+Pre-deployment disk inspection checklist (model, size, SMART, power-on hours, wear/endurance,
+sector errors, temperature, firmware): `docs/RUNBOOK_DISK_FAILURE.md`'s inspection section —
+run once, against the real drives, before committing to a layout.
+
+## 5-8. Network, firewall, Docker TLS, public ingress
+
+Full detail: `docs/PRODUCTION_NETWORK_SECURITY.md`. Summary: two private VM networks, Docker TLS
+(mutual, already application-supported since Phase 1 — this phase only needed the certificate
+generation/deployment automation, not new app code), a single public origin (Caddy, automatic
+HTTPS) proxying only to the Gateway, and one genuinely new architectural item this phase
+surfaced and addressed at the network-policy layer: **Gateway-to-Lab reachability across two
+real VMs** — see that doc's dedicated section for what's built vs. what still needs a small,
+reviewed Provisioner/Gateway code change before real go-live.
+
+## 9-10. Production auth/cookie config, secrets
+
+`infra/environments/production/*.env.template` set `COOKIE_SECURE=1`/`TRUST_PROXY=1` explicitly
+(dev's unsafe defaults are never inherited). Secrets: Ansible Vault (already bundled with
+Ansible — no new tool to install/trust for this project's secret surface), template at
+`infra/ansible/group_vars/production.vault.yml.template`. Nothing is committed —
+`infra/.gitignore` covers `*.env`, TLS private key material, vault plaintext, Terraform state.
+
+## 11-13. Postgres, backup, DR
+
+Full detail: `docs/BACKUP_DR.md`. Summary: conservative tuning baseline (not hand-tuned before
+real RAM is known), daily encrypted backups with an off-host adapter point (Storage Box/S3/any
+SSH target), and a **real, tested** backup→encrypt→restore→verify cycle
+(`infra/backup/test-backup-restore.sh`) — run against disposable local Postgres with the actual
+production migrations applied, not a mock.
+
+## 14-17. Observability, logging, alerting, uptime
+
+Full detail: `docs/OBSERVABILITY.md`. Prometheus + Grafana + Loki/Promtail (the user's stated
+Prometheus/Grafana preference, honored) + Alertmanager, all self-hosted, no paid dependency.
+Deliberately does not duplicate the application's own instructor learning analytics
+(Phase 3B) — operational observability and learning analytics stay separate concerns with
+separate audiences, per the explicit instruction. Application-level metrics (active
+students/Labs, provisioning failures, Gateway error rate) are a documented, **not-yet-built**
+follow-up — see that doc's honest accounting of what's real today (host/container/Postgres
+metrics, HTTP healthz probes) vs. what needs app instrumentation later.
+
+## 18-19. CI/CD, image strategy
+
+`infra/ci/gitea-workflows/build-and-test.yml` — automatic test/build/tag/staging-deploy,
+**manual** production promotion (`infra/scripts/deploy-production.sh`), matching the stated
+preference. SHA-tagged images always, semantic tags on deliberate releases, never `:latest` in
+staging/production. Full detail: `infra/docker/IMAGE_STRATEGY.md`.
+
+## 20-21. Ansible, Terraform
+
+`infra/ansible/site.yml` — idempotent roles, doesn't assume the VMs already exist (Terraform
+creates them first). Real `ansible-playbook --syntax-check` pass. `infra/terraform/` — real
+`tofu validate` pass against the actual `bpg/proxmox` provider schema. Neither installs Proxmox
+itself or builds the base VM template — both stay deliberate manual, documented, one-time steps
+(`infra/proxmox/README.md`), per the explicit "don't over-automate the fragile one-time step"
+instruction.
+
+## 22-23. Environment config, staging
+
+`infra/environments/{dev,staging,production}/` — explicit separation, production never
+inherits dev defaults. Staging is designed to run in the homelab or a resource-constrained
+slice of the real server later — no second dedicated server required.
+
+## 24-25. Load testing, capacity model
+
+`infra/scripts/loadtest/` (real Prepare-Labs-driven boot test + `docker stats` sampling) and
+`infra/scripts/capacity-model.js` (a real, working worksheet — tested against example inputs,
+produces CPU-vs-memory-bound recommended/warning/hard-admission-control thresholds). No
+concurrency number is hard-coded as a marketing figure; the example config in
+`infra/environments/production/capacity.yml.example` is explicitly flagged as placeholder data.
+
+## 26-27. Validation checklist, runbooks
+
+`docs/PRODUCTION_VALIDATION_CHECKLIST.md` — one master checklist spanning hardware through
+academy-workflow verification. 12 runbooks (`docs/RUNBOOK_*.md`) — first deployment, normal
+deploy, rollback, Postgres restore, VM rebuild (both hosts), Docker TLS rotation, TLS renewal,
+owner recovery, stuck Lab cleanup, failed migration, backup failure, disk failure, Lab Host
+resource pressure.
+
+## What this phase deliberately did NOT touch
+
+Learning system design, curriculum content, RBAC model, session architecture — all Phase 3A/3B,
+unchanged. No parent portal, billing, held scenarios, or production OIDC provider integration.
+RootNode production infrastructure is dedicated to RootNode Academy — never folded into
+existing Synthos production servers, and canonical source stays Gitea, never GitHub `kubekosh`.
+
+## Known gap surfaced during this phase (not silently papered over) — RESOLVED in Phase 4.1
+
+Building the real production Compose/network config surfaced that the Gateway's existing
+mechanism for reaching a Lab container (`env.internal_ip`, a Docker-bridge-local address) only
+works when Gateway and Lab share a Docker daemon — true in every dev/single-host setup so far,
+**not** true once Labs run on a genuinely separate `rn-lab-host-01`. At the time this phase
+closed, the network-policy half was built but the application half was flagged as an explicit,
+not-yet-built follow-up rather than guessed at mid-infra-phase.
+
+**Phase 4.1 (`docs/PHASE4_1_PREPRODUCTION_HARDENING.md` §1) built and proved the application
+half** — a Lab Host Router (`platform/lab-router/`) plus a `labTarget()` routing abstraction in
+the Gateway, real-tested against a genuine two-network Docker simulation
+(`infra/scripts/simulate-two-host/`), not just designed. See
+`docs/PRODUCTION_NETWORK_SECURITY.md`'s "Gateway-to-Lab reachability" section for the full
+resolution. This item no longer blocks real two-VM go-live.

docs/PRODUCTION_DEPLOYMENT.md

@@ -0,0 +1,90 @@
+# Production Deployment
+
+Step-by-step, for when the real Hetzner host exists. See
+`docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md` for the architecture this executes.
+
+## 0. One-time, manual, not automated (deliberately)
+
+1. Install Proxmox VE on the bare-metal host — `infra/proxmox/README.md`.
+2. Inspect the real disks, pick a ZFS layout — `docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md` §4,
+   `docs/RUNBOOK_DISK_FAILURE.md`'s inspection checklist.
+3. Build the cloud-init VM template Terraform will clone —
+   `infra/proxmox/cloud-init/user-data.yaml` + `infra/proxmox/README.md`.
+4. Fill in `infra/terraform/terraform.tfvars` (copy from `.tfvars.example`) with the real
+   Proxmox API endpoint, node name, storage/datastore names, and chosen VM sizes.
+5. Fill in `infra/ansible/inventory/production.ini` with the real VM IPs, and
+   `infra/ansible/group_vars/production.yml` with `platform_ip`, `lab_host_ip`,
+   `management_cidr`, `proxmox_mgmt_cidr`.
+6. Copy `infra/ansible/group_vars/production.vault.yml.template` →
+   `production.vault.yml`, fill in every `vault_*` secret with real generated values, then
+   `ansible-vault encrypt group_vars/production.vault.yml`. Never commit the plaintext.
+
+## 1. Create the VMs
+
+```bash
+cd infra/terraform
+tofu init
+tofu plan    # review before applying against real hardware
+tofu apply
+```
+
+Creates `rn-platform-01` and `rn-lab-host-01` from the cloud-init template. Confirm both boot
+and are SSH-reachable from the management network before continuing.
+
+## 2. Generate TLS certificates (offline, once)
+
+```bash
+export ROOTNODE_TLS_BUNDLE_DIR=/secure/offline/path   # never inside the repo
+./infra/scripts/docker-tls/generate-docker-tls.sh
+./infra/scripts/docker-tls/verify-docker-tls.sh
+```
+
+Generates FOUR leaf certs under one CA (Phase 4.1 extended this from two): the CONTROL-plane
+pair (`server-*`/`provisioner-client-*`, for Provisioner↔dockerd) and the DATA-plane pair
+(`router-server-*`/`gateway-client-*`, for Gateway↔Lab Host Router — see
+`docs/PRODUCTION_NETWORK_SECURITY.md`'s "control plane vs data plane" section). The CA private
+key stays in `ROOTNODE_TLS_BUNDLE_DIR` and never touches either VM — only the CA cert (public)
+and each host's own leaf cert+key go to each host, both pairs deployed by the same `docker-tls`
+Ansible role into two separate directories (`/etc/rootnode/docker-tls/` and
+`/etc/rootnode/lab-router-tls/`).
+
+## 3. Configure both hosts
+
+```bash
+cd infra/ansible
+ansible-playbook -i inventory/production.ini site.yml --ask-vault-pass
+```
+
+Role order matters and is fixed in `site.yml`: `common` → `firewall` → `docker-tls` →
+`platform`/`lab-host` → `monitoring-agent` → `backup`. Firewall and TLS land before anything
+that depends on them.
+
+## 4. First application deploy
+
+```bash
+./infra/scripts/deploy-production.sh <image-tag>
+```
+
+Pulls the tagged images, runs the compose stack, applies Postgres migrations (automatic, on
+Platform API/Provisioner startup — see `docs/RUNBOOK_FAILED_MIGRATION.md` if one fails).
+
+## 5. Verify
+
+```bash
+./infra/scripts/production-smoke-test.sh
+```
+
+Curls `/healthz` on the Gateway and Platform API, confirms Postgres is reachable, confirms
+Prometheus/Grafana/Alertmanager are up. Then walk
+`docs/PRODUCTION_VALIDATION_CHECKLIST.md` in full before calling the deployment live.
+
+## Normal (non-first) deploys
+
+`docs/RUNBOOK_NORMAL_DEPLOY.md`. Rollback: `docs/RUNBOOK_ROLLBACK.md`.
+
+## What this document does NOT cover
+
+DNS/Cloudflare setup for the public origin (a one-time manual step outside this repo's scope —
+point the A/AAAA record at the real host and confirm Caddy issues its certificate). Which
+storage layout to pick (decision framework only, §4 of the master doc — the real answer depends
+on the real disks).

docs/PRODUCTION_NETWORK_SECURITY.md

@@ -0,0 +1,130 @@
+# Production Network & Security
+
+The Platform VM / Lab Host VM boundary is the core production control. This document is where
+every network decision that touches it gets written down. Nothing here weakens it.
+
+## Topology
+
+```
+Internet ──HTTPS(443)──▶ Caddy (rn-platform-01) ──▶ Gateway (internal bridge)
+                                                        │
+management_cidr ──SSH──▶ rn-platform-01                │
+management_cidr ──SSH──▶ rn-lab-host-01                 │
+proxmox_mgmt_cidr ──22/8006──▶ Proxmox host             │
+                                                        │
+rn-platform-01 (Provisioner) ──TLS:2376──▶ rn-lab-host-01 (dockerd)          [CONTROL plane]
+rn-platform-01 (Gateway) ──mTLS:8443──▶ rn-lab-host-01 (Lab Host Router)     [DATA plane]
+rn-lab-host-01 (promtail) ──3100──▶ rn-platform-01 (Loki)
+rn-lab-host-01 (node-exporter/cadvisor) ◀──scrape── rn-platform-01 (Prometheus)
+```
+
+Firewall source of truth: `infra/firewall/{proxmox-host,rn-platform-01,rn-lab-host-01}.rules`
+(iptables-restore format, deployed by the `firewall` Ansible role). Validate with
+`infra/firewall/validate-firewall.sh`.
+
+## What is explicitly denied
+
+- Student Lab → another student Lab (no student-to-student traffic, ever).
+- Student Lab → Proxmox management (both the host firewall and the `lab_subnet_range` DENY
+  rule in `rn-lab-host-01.rules`).
+- Student Lab → Platform Postgres / Platform API / Gateway internals (logged DENY in
+  `rn-platform-01.rules` for anything from `lab_host_ip` to ports 5432/4100).
+- rn-lab-host-01 → Postgres (same rule — the Lab Host itself has no legitimate reason to reach
+  Postgres; only the Provisioner on rn-platform-01 does, and it talks to Postgres over the
+  internal Docker bridge, never across the VM boundary).
+- Any student egress except through the approved egress proxy (enforced by the Provisioner's
+  existing per-Lab `DOCKER-USER` chain manipulation from Phase 1 — unchanged by this phase).
+- Direct public exposure of the Provisioner, Postgres, Docker TLS port, Proxmox UI, or Grafana
+  (Grafana is reachable only via Caddy's `/grafana/*` path, itself restricted to
+  `management_cidr` by a `caddy` matcher — see `infra/docker/platform/Caddyfile.j2`).
+
+## Control plane vs data plane (Phase 4.1 §10)
+
+Two separate, never-conflated mTLS connections between the two VMs, deliberately kept apart
+both conceptually and operationally:
+
+| | Control plane | Data plane |
+|---|---|---|
+| What | Provisioner manages Lab containers | Gateway serves student browser traffic |
+| Path | Provisioner → dockerd (port 2376) | Gateway → Lab Host Router (port 8443) |
+| Who initiates | Provisioner only | Gateway only |
+| What it can do | Create/start/stop/remove containers, full Docker API | Reverse-proxy one HTTP/WS request to one already-running container by opaque token — nothing else |
+| Certs | `provisioner-client-*` / `server-*` | `gateway-client-*` / `router-server-*` |
+| Exposes Docker API to caller? | Yes (that's its job — Provisioner IS a Docker client) | **Never** — the Router never exposes Docker API, container IDs, or network info to its caller |
+
+The student browser's traffic is proxied at the Gateway/Router layer and never touches the
+Docker API at any point — the Router deliberately has no route that echoes back anything
+Docker-internal (see `platform/lab-router/src/server.js`'s header comment for the full "narrow
+by design" list).
+
+## Docker TLS (Provisioner ↔ Lab Host)
+
+Mutual TLS on port 2376, restricted at the firewall to `platform_ip` only. Application support
+already existed since Phase 1 (`platform/provisioner/src/docker.js`'s `buildClient()`); this
+phase added the operational half: `infra/scripts/docker-tls/generate-docker-tls.sh` (CA +
+server + client cert generation), the `docker-tls` Ansible role (deploys certs, configures
+`dockerd`'s `daemon.json`), and `docs/RUNBOOK_DOCKER_TLS_ROTATION.md` for renewal. The CA
+private key is generated offline and never committed or deployed to either VM — only the CA
+cert (to verify the peer) and each host's own leaf cert+key.
+
+## Public ingress
+
+One origin, Caddy, automatic HTTPS. `reverse_proxy gateway:4200` — Caddy talks only to the
+Gateway; nothing else is proxied. WebSocket upgrade works automatically (Caddy's default
+`reverse_proxy` behavior, no special config needed for the terminal WebSocket path). Whether to
+front this with Cloudflare or expose the origin directly is left as a deployment-time decision
+(both work with Caddy's ACME flow; Cloudflare adds DDoS absorption at the cost of Cloudflare
+being able to see plaintext unless "Full (strict)" mode is used) — not decided here since it
+doesn't affect anything else in this document.
+
+## Gateway-to-Lab reachability across two real VMs — RESOLVED in Phase 4.1
+
+Phase 4 flagged this as the single most important open item; Phase 4.1
+(`docs/PHASE4_1_PREPRODUCTION_HARDENING.md` §1) closed it. Kept here as the historical record of
+what the gap was and how it was closed, since the reasoning matters for anyone extending this
+later (e.g. adding a second Lab Host).
+
+**The gap, as originally found:** the Gateway used to reach a running Lab container via
+`env.internal_ip` — a Docker bridge-local address recorded by the Provisioner when it creates
+the container. That only works when Gateway and the Lab share a Docker daemon, true in dev and
+any single-host setup, false the moment Labs run on a genuinely separate `rn-lab-host-01`.
+
+**The fix — a Lab Host Router (`platform/lab-router/`):** a small, narrow service that runs on
+rn-lab-host-01 (host-networked, like `egress-proxy`, so it can reach whatever per-Lab bridge
+network the Provisioner creates) and does exactly one thing: given an opaque routing token over
+mTLS, find the ONE local container labeled with that token (`docker ps --filter
+label=rootnode.routing-token=<token>` — resolved purely from local Docker state, no Postgres,
+no call back to the Provisioner) and reverse-proxy the request to it, HTTP and WebSocket both.
+
+The Gateway now decides `direct` vs `router` per `lab_host` (`lab_hosts.routing_mode` +
+`router_endpoint`, `platform/provisioner/migrations/004_lab_hosts_routing.sql`) via
+`platform/gateway/src/lab-endpoint.js` — a single function, `labTarget(env, token)`, that every
+proxy/fetch call site in `server.js` goes through instead of building
+`http://${env.internal_ip}:${env.internal_port}` itself. `dev-local` stays `direct` (T480/local
+dev unaffected, zero behavior change there); a real `rn-lab-host-01` is configured `router`.
+
+**Firewall (`infra/firewall/rn-lab-host-01.rules`):** the old speculative
+`lab_gateway_port_range` allowance (which assumed option (a), publishing per-Lab ports) was
+replaced with a single, narrow rule: `platform_ip` → port `{{ lab_router_port | default('8443')
+}}` only. No wide port range, no per-Lab port publishing at all — the Router is the only thing
+the Gateway ever talks to on rn-lab-host-01 for Lab traffic.
+
+**mTLS:** the Gateway↔Router pair uses the SAME private CA as the Provisioner↔dockerd pair
+(`infra/scripts/docker-tls/generate-docker-tls.sh`, extended in Phase 4.1 to also issue
+`router-server`/`gateway-client` leaf certs), deployed to a separate directory
+(`/etc/rootnode/lab-router-tls/`) by the same `docker-tls` Ansible role.
+
+**Proven, not just designed:** `infra/scripts/simulate-two-host/` builds a real two-network
+Docker simulation (Gateway genuinely isolated on its own bridge, no route to any Lab's bridge)
+and runs 13 real assertions against it — Gateway cannot reach a Lab's Docker-internal IP
+directly, but reaches it correctly through the Router (HTTP and a real WebSocket
+`kubectl get nodes`), Alice/Bob isolation holds, garbage/destroyed tokens are rejected, and the
+Router itself refuses any connection without the Gateway's client certificate. See that
+directory's README for exactly what is and isn't proven by a same-daemon simulation versus real
+separate hardware.
+
+## Cookie / auth production settings
+
+`infra/environments/production/*.env.template`: `COOKIE_SECURE=1`, `TRUST_PROXY=1`. Dev's
+insecure defaults (`COOKIE_SECURE` unset, no proxy trust) are never inherited — production env
+files are separate files, not a dev file with overrides layered on.

docs/PRODUCTION_VALIDATION_CHECKLIST.md

@@ -0,0 +1,58 @@
+# Production Validation Checklist
+
+Walk this once, top to bottom, before calling a production deployment live. Every item here
+needs the real hardware — this is the "DEPLOY LATER" half of Phase 4, not something this repo
+can prove in advance.
+
+## Hardware / Proxmox
+- [ ] Disk inspection done, layout chosen and matches what's actually in the server (`docs/RUNBOOK_DISK_FAILURE.md` inspection checklist, `docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md` §4)
+- [ ] Proxmox VE installed, reachable only from `management_cidr`/`proxmox_mgmt_cidr`
+- [ ] VM template built from real cloud-init (`infra/proxmox/README.md`)
+- [ ] `tofu apply` created both VMs; both boot and are SSH-reachable
+
+## Platform VM
+- [ ] `ansible-playbook site.yml` completed clean, all roles
+- [ ] `docker compose ps` shows every service healthy (postgres, provisioner, api, gateway, reverse-proxy, prometheus, alertmanager, grafana, loki, promtail, exporters)
+- [ ] `curl https://<origin>/healthz` (via Gateway) returns 200
+- [ ] `curl http://localhost:4300/healthz` (Platform API, from the VM) returns `{"ok":true,"db":"ok"}`
+- [ ] TLS certificate issued and valid for the real domain
+
+## Lab Host VM
+- [ ] Docker daemon TLS verified: `docker --tlsverify --tlscacert=... -H tcp://<lab_host_ip>:2376 info` succeeds from the Platform VM, fails from anywhere else
+- [ ] Lab Host Router mTLS verified: a request to `https://<lab_host_ip>:8443` with no client cert is rejected; with the Gateway's real client cert it isn't (mirrors `infra/scripts/simulate-two-host/test-remote-routing.js`'s "direct public access: NOT AVAILABLE" case, now against the real host)
+- [ ] Provisioner successfully creates a real Lab against the real Lab Host
+- [ ] Gateway can actually reach that Lab's terminal (HTTP UI load + WebSocket `kubectl` command) — application mechanism built and simulation-tested in Phase 4.1 (`docs/PHASE4_1_PREPRODUCTION_HARDENING.md` §1/§6/§7); this line is the real-hardware confirmation that the same result holds across the actual two VMs, not two Docker networks on one daemon
+- [ ] Egress proxy correctly restricts a Lab's outbound traffic (Provisioner's per-Lab `DOCKER-USER` chain)
+
+## Security
+- [ ] `infra/firewall/validate-firewall.sh` run against the real hosts with real `iptables-restore --test`, not just the structural lint
+- [ ] Confirm from an unauthorized IP: Postgres, Provisioner, Docker TLS port, Proxmox UI are all unreachable
+- [ ] Confirm Student Lab → another Lab is blocked; confirm Student Lab → Proxmox is blocked
+- [ ] `COOKIE_SECURE`/`TRUST_PROXY` active (check a real Set-Cookie header over HTTPS)
+
+## Academy (application-level smoke test)
+- [ ] Owner bootstrap login works
+- [ ] Instructor can create a cohort, roster a student
+- [ ] Student can log in, boot a Lab, complete a scenario, see progress
+- [ ] An assessment can be assigned, taken, and graded end-to-end
+- [ ] Instructor analytics dashboards populate with real data
+
+## Backup
+- [ ] Manual `backup-postgres.sh` run succeeds against real Postgres, real off-host target reachable
+- [ ] A real restore (`restore-postgres.sh` + `verify-restore.sh`) has been rehearsed at least once against a throwaway target, not just the local test harness — Phase 4.1's `infra/backup/test-destructive-restore-drill.sh` proved the full mechanism (realistic data, real storage destruction, restore, real Platform API boot) locally; this line is the real-hardware confirmation
+- [ ] Cron job confirmed scheduled (`crontab -l`)
+
+## Observability
+- [ ] Grafana dashboard shows real data for both VMs
+- [ ] Trigger one alert deliberately (e.g. stop a service) and confirm it fires and reaches the webhook
+- [ ] Loki has logs flowing from both VMs
+
+## Pre-production hardening (Phase 4.1 — see docs/PHASE4_1_PREPRODUCTION_HARDENING.md)
+- [ ] `resource-policy.yaml`'s `admission_control.max_concurrent_labs` set from a real measured
+      `infra/scripts/capacity-model.js` run against the real Lab Host, not left disabled
+- [ ] A deliberate over-capacity attempt returns the clean 503 "Lab capacity is temporarily
+      full" message, not a 500 — confirms the real host's admission control matches the local test
+- [ ] `docs/RUNBOOK_LAB_HOST_RESOURCE_PRESSURE.md`'s steps still make sense once capacity numbers are real
+
+Only once every box above is checked against the real server does the deployment graduate from
+"infrastructure package built" to "actually in production."

docs/REMOTE_AND_SELF_PACED_ARCHITECTURE.md

@@ -0,0 +1,85 @@
+# Remote & Self-Paced Delivery Architecture
+
+Phase 4.1 §12. This is an architecture review, not a new product — no self-registration,
+payments, or public enrollment is built here (explicit non-goal). The question this document
+answers: does the infrastructure and application assume "an instructor always provisions the
+Lab," and if so, where, and what would need to change for self-paced delivery to work.
+
+## The short answer: less of that assumption exists than expected
+
+RootNode Academy's Lab lifecycle was built student-driven from Phase 1 — `POST
+/api/environment/launch` is called by the STUDENT'S OWN session, not by an instructor action.
+"Prepare Labs" (`POST /api/admin/cohorts/:id/prepare-labs`) is a classroom **convenience** that
+front-loads several students' launches at once before a synchronous class session, not the only
+path to a running Lab. This was true before Phase 4.1 and confirmed still true by this phase's
+own regression suites (`platform/test/e2e-phase2a.js` roster's two students with `cohort_id:
+null` and takes them through login → curriculum → launch → scenario work with zero cohort
+involvement) and by two new Phase 4.1 drills built specifically to exercise the remote/returning
+-student narrative:
+
+- `infra/scripts/drills/test-lab-host-loss.js` — student launches, makes progress, their Lab is
+  destroyed out from under them (standing in for an idle-reaper destroy), Platform stays up,
+  progress is untouched, they launch again unprompted and continue.
+- `infra/scripts/drills/test-fake-cohort-rehearsal.js` — the same "returns later, fresh Lab,
+  curriculum continues" narrative as part of a fuller classroom rehearsal.
+
+Both pass today, with zero application code changes needed for the self-paced-relevant parts of
+this flow specifically — see the Phase 4.1 report for the full run results.
+
+## What already works, unmodified
+
+- **Student-initiated provisioning** — no instructor step is required between "student wants to
+  work" and "Lab exists." (`platform/api/src/server.js`'s `/api/environment/launch`.)
+- **Cohort-less students** — `cohort_id` is nullable on student creation
+  (`POST /api/admin/students`); a student with no cohort logs in, sees the curriculum, launches
+  Labs, and makes progress identically to a cohorted one. Confirmed by inspection AND by the
+  existing regression suite, not just by schema reading.
+- **Idle reaper → academic state survives → return → continue** — the exact lifecycle this
+  section describes as the target self-paced experience is what Phase 1's reaper +
+  Phase 2B's Postgres-backed academic data (separate from the disposable Lab) were already
+  designed to produce. Phase 4.1 proved it end-to-end, twice (see above).
+- **Curriculum content itself is not cohort-gated** — `GET /api/curriculum/path` reads the one
+  curriculum path file directly (`curriculum.loadCurriculumPath()`); it never checks
+  `curriculum_assignments` or cohort membership at all. A self-paced student sees the full
+  curriculum with no instructor action required to "unlock" it.
+
+## What's genuinely missing for a real self-paced product (Phase 5, not built here)
+
+1. **No self-registration / public enrollment.** A student row is created only by an instructor
+   (`POST /api/admin/students`, admin/owner RBAC-gated). There is no public "sign up" surface.
+   This is almost certainly the right call to leave alone for now — it's explicitly a Phase 5+
+   product/business decision (course commerce, is it free, who's allowed to enroll), not an
+   infrastructure gap.
+
+2. **No real student authentication.** A student session is created from a bare `student_id`
+   (`POST /api/login`, no password) — deliberately, since today every `student_id` is issued and
+   controlled by an instructor via the roster, not chosen or known by the public. A genuinely
+   remote/self-paced product where students access their account without an instructor in the
+   loop needs real credentials (email+password, or a magic link) — reusing the same
+   `password_hash`/`scrypt` machinery `instructors` already has (`src/auth/password.js`) would
+   be the natural extension, not a new auth system. **This is the one item on this list that
+   would actually block self-paced delivery today** — everything else already works or is a
+   product decision, not an infrastructure one.
+
+3. **`curriculum_assignments.student_id` is schema-ready but unwired.** The table has supported
+   a direct per-student curriculum assignment (independent of any cohort) since Phase 2B
+   (`CONSTRAINT curriculum_assignment_target CHECK (cohort_id IS NOT NULL OR student_id IS NOT
+   NULL)`) — but nothing in the application ever reads or writes that column today; there's only
+   one curriculum path, so nothing has needed to differentiate yet. Not a gap that blocks
+   self-paced delivery now (every student already sees the one path with no gate), but the
+   moment a second curriculum path exists, this is where per-individual assignment lands — the
+   schema was designed for exactly this and doesn't need a migration to support it.
+
+4. **No delivery-mode concept anywhere.** In-person, remote, and self-paced sessions aren't
+   distinguished in any data model today, and nothing currently needs them to be — capacity
+   planning, the reaper, and academic records all behave identically regardless of how a student
+   is attending. Worth being aware this is unmodeled, not worth building a taxonomy for before a
+   real product reason exists (YAGNI).
+
+## What Phase 4.1 deliberately did NOT do here
+
+No signup flow, no student password/email auth implementation, no per-student curriculum
+assignment route, no payments, no public course catalog, no held/premium scenario content. All
+explicit non-goals per this phase's authorization. This document exists so Phase 5 planning
+starts from an accurate picture of the gap (one real item: student authentication) instead of a
+guess.

docs/RUNBOOK_BACKUP_FAILURE.md

@@ -0,0 +1,31 @@
+# Runbook: Backup Failure
+
+Triggered by the `BackupFailed`/`BackupAging` alerts (`infra/monitoring/prometheus/rules/rootnode.yml`).
+
+```bash
+# 1. See what actually happened — the cron wrapper logs to syslog
+journalctl -u rootnode-backup --since "24 hours ago" -o cat
+# or, if the cron job never even ran:
+grep rootnode-postgres-backup /var/log/syslog
+
+# 2. Run it manually to see the failure live
+source /etc/rootnode/backup.env
+/opt/rootnode/backup/backup-postgres.sh
+```
+
+**Common causes:**
+- Disk full on `{{ rootnode_data_root }}/backups` — check `df -h`, prune more aggressively
+  (`BACKUP_RETENTION_DAYS`) or the ZFS dataset needs more space (see `docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md` §4).
+- Off-host target unreachable (`BACKUP_OFFSITE_TARGET`) — check the SSH key/credentials
+  haven't expired, the target host/bucket is reachable: `ssh <offsite-target-host> echo ok` or
+  the equivalent for whatever adapter is configured (`docs/BACKUP_DR.md`).
+- `BACKUP_ENCRYPTION_PASSPHRASE` missing/wrong in `/etc/rootnode/backup.env` — re-check against
+  the value in Ansible Vault (`vault_backup_encryption_passphrase`); a mismatch here means even
+  a "successful" old backup becomes unrestorable, so treat this specific failure mode as urgent.
+- The dump itself is suspiciously small (script's own sanity check tripped) — Postgres may be
+  unhealthy; check `docker exec rootnode-platform-postgres-1 pg_isready` first.
+
+**After fixing:** run the backup manually once to confirm success (metric updates immediately,
+alert clears within one Prometheus scrape interval), then confirm the cron job is still
+correctly scheduled (`crontab -l` as root, or re-run the `backup` Ansible role if the cron entry
+itself is suspect).

docs/RUNBOOK_DISK_FAILURE.md

@@ -0,0 +1,44 @@
+# Runbook: Disk Failure
+
+Applies once real hardware/ZFS exists — see `docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md` §4 for
+the storage decision framework this assumes (mirrored vdevs, never single-disk for Postgres).
+
+```bash
+# 1. Confirm the failure
+zpool status -v
+smartctl -a /dev/sdX   # the suspect drive
+
+# 2. If it's a mirrored vdev (the required layout for anything holding Postgres data — see §4),
+#    the pool stays online in DEGRADED state. No immediate data-loss risk, but no redundancy
+#    either until replaced — treat DEGRADED as urgent, not routine.
+zpool status   # confirm DEGRADED, not FAULTED/UNAVAIL (those mean act immediately, possibly
+                # restore from backup if the redundant mirror side is also compromised)
+
+# 3. Replace the physical drive, then:
+zpool replace <pool> <old-device> <new-device>
+zpool status   # watch the resilver progress
+
+# 4. If a whole pool was lost (both mirror sides failed simultaneously — the scenario mirroring
+#    exists to make vanishingly unlikely, but plan for it anyway):
+#    - rn-lab-host-01's disposable data: nothing to recover, just rebuild the VM
+#      (docs/RUNBOOK_VM_REBUILD.md)
+#    - rn-platform-01's Postgres data: restore from the latest off-host backup
+#      (docs/RUNBOOK_POSTGRES_RESTORE.md) — this is exactly the scenario off-host backup
+#      copies exist for; a local-only backup on the SAME failed pool would be useless here
+```
+
+**Pre-deployment disk inspection checklist** (run once when the real drives are known, before
+they go into service — `docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md` §4):
+
+```bash
+for d in /dev/nvme0n1 /dev/nvme1n1 /dev/nvme2n1 /dev/nvme3n1; do   # adjust to real device names
+  echo "== $d =="
+  smartctl -i "$d" | grep -E 'Model|Serial|Capacity|Firmware'
+  smartctl -A "$d" | grep -iE 'power_on_hours|reallocated|pending|uncorrectable|wear|percentage.used|temperature'
+  smartctl -H "$d" | grep -i overall
+done
+```
+Record model, size, power-on hours, wear/endurance percentage, reallocated/pending sector
+counts, temperature, and firmware version for every drive before committing to a ZFS layout —
+a drive already showing wear or reallocated sectors shouldn't be trusted with Postgres data
+even in a mirror.

docs/RUNBOOK_DOCKER_TLS_ROTATION.md

@@ -0,0 +1,31 @@
+# Runbook: Docker TLS Rotation
+
+Rotate on a schedule (recommend yearly, well before the ~2.25-year cert lifetime
+`generate-docker-tls.sh` defaults to) or immediately if a client cert may have leaked.
+
+```bash
+# 1. Generate a fresh bundle (new CA too — simplest, avoids any question about whether the old
+#    CA's private key was ever exposed)
+cd infra/scripts/docker-tls
+./generate-docker-tls.sh --out-dir ./out-$(date +%Y%m%d) --lab-host-ip <real-ip> --lab-host-dns rn-lab-host-01.internal
+./verify-docker-tls.sh ./out-$(date +%Y%m%d)
+
+# 2. Redeploy — this restarts dockerd on rn-lab-host-01 (brief interruption to any in-flight
+#    Docker API call from the Provisioner, NOT to already-running student Labs — their
+#    containers keep running through a dockerd restart)
+cd ../../ansible
+ROOTNODE_TLS_BUNDLE_DIR=../scripts/docker-tls/out-$(date +%Y%m%d) \
+  ansible-playbook site.yml -i inventory/production.ini --tags docker-tls --ask-vault-pass
+
+# 3. Verify the Provisioner can still reach rn-lab-host-01
+curl -s http://localhost:4100/health   # from rn-platform-01
+```
+
+**Troubleshooting a failed rotation:**
+- `x509: certificate signed by unknown authority` — the new ca.pem wasn't deployed to both
+  sides, or an old one is cached; re-run the docker-tls role on BOTH hosts.
+- Provisioner logs `ECONNREFUSED` on port 2376 — dockerd didn't actually restart with the new
+  daemon.json; check `systemctl status docker` on rn-lab-host-01 and the ExecStart override
+  (`infra/ansible/roles/docker-tls/templates/docker-override.conf.j2`) actually applied.
+- Firewall — confirm `infra/firewall/rn-lab-host-01.rules`' 2376 rule still matches
+  rn-platform-01's actual IP (didn't change as part of this rotation, but worth a sanity check).

docs/RUNBOOK_FAILED_MIGRATION.md

@@ -0,0 +1,35 @@
+# Runbook: Failed Migration
+
+Both Platform API and Provisioner apply their own migrations automatically on startup
+(`platform/api/src/db.js`, `platform/provisioner/src/db.js`), file-tracked in
+`schema_migrations`, wrapped in a transaction per file — a migration either fully applies or
+fully rolls back, it can't leave a table half-altered.
+
+**If a deploy fails because a migration errored:**
+
+```bash
+# 1. Check what actually happened
+docker logs rootnode-platform-api-1 --tail 50   # the error is right there — migration file + message
+docker exec -it rootnode-platform-postgres-1 psql -U rootnode_platform -c \
+  "SELECT * FROM schema_migrations ORDER BY applied_at DESC LIMIT 10;"
+
+# 2. Since the failing migration's transaction rolled back, the schema is still in its
+#    PREVIOUS valid state — the app just won't start until the migration succeeds. Fix the
+#    root cause (usually a real data issue the migration didn't anticipate, or the
+#    cross-service ordering dependency — Provisioner's migrations must run before Platform
+#    API's, since scenario_attempts has a real FK to environments; see
+#    docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md).
+
+# 3. Redeploy once fixed — the migration runner is idempotent and will just pick up where it
+#    left off; already-applied migrations are skipped.
+./infra/scripts/deploy-production.sh <same-or-fixed-tag>
+```
+
+**If you need to roll back the CODE but the migration already succeeded** (schema changed,
+code that depended on it is being reverted): rolling back application images
+(`docs/RUNBOOK_ROLLBACK.md`) does NOT undo a Postgres migration — there is no automatic
+down-migration mechanism (deliberate, matches the existing check-before-alter, additive-only
+migration convention documented in `docs/ENGINEERING_SOP.md` §6). If the old code genuinely
+can't run against the new schema, restore from the pre-migration backup instead
+(`docs/RUNBOOK_POSTGRES_RESTORE.md`) rather than trying to hand-write a down-migration under
+pressure.

docs/RUNBOOK_FIRST_DEPLOYMENT.md

@@ -0,0 +1,34 @@
+# Runbook: First Production Deployment
+
+Prerequisites: Proxmox installed (`infra/proxmox/README.md`), VMs created
+(`infra/terraform/`), DNS pointed at rn-platform-01's public IP.
+
+```bash
+# 1. Generate Docker TLS material (offline, on your own machine — never on either VM)
+cd infra/scripts/docker-tls
+./generate-docker-tls.sh --out-dir ./out --lab-host-ip <real-lab-host-ip> --lab-host-dns rn-lab-host-01.internal
+./verify-docker-tls.sh ./out
+
+# 2. Fill in real values
+cd ../../ansible
+cp group_vars/production.vault.yml.template group_vars/production.vault.yml
+$EDITOR group_vars/production.vault.yml   # real passwords/secrets — openssl rand -hex 32 etc.
+ansible-vault encrypt group_vars/production.vault.yml
+$EDITOR group_vars/production.yml         # real IPs, domain, CIDRs
+$EDITOR inventory/production.ini          # real IPs
+
+# 3. Deploy
+ROOTNODE_TLS_BUNDLE_DIR=../scripts/docker-tls/out \
+  ansible-playbook site.yml -i inventory/production.ini --ask-vault-pass
+
+# 4. Bootstrap the owner account (once, by a human)
+ssh rootnode-deploy@rn-platform-01
+docker exec -it rootnode-platform-api-1 node bootstrap-owner.js [email protected] "Your Name"
+# (password comes from BOOTSTRAP_OWNER_PASSWORD in the environment, or the CLI prompt — see
+# platform/api/README.md)
+
+# 5. Verify
+../../infra/scripts/production-smoke-test.sh
+```
+
+Then work through `docs/PRODUCTION_VALIDATION_CHECKLIST.md` in full before calling this done.

docs/RUNBOOK_LAB_HOST_RESOURCE_PRESSURE.md

@@ -0,0 +1,29 @@
+# Runbook: High Lab Host Resource Pressure
+
+Triggered by the `LabHostHighMemory`/`HighDiskUsage` warning alerts.
+
+```bash
+# 1. How many Labs are actually running, and against what admission-control threshold?
+curl -s http://localhost:4100/environments | jq '[.[] | select(.status=="running")] | length'
+node infra/scripts/capacity-model.js   # recommended/warning/hard thresholds
+
+# 2. If genuinely over capacity: this is expected pressure from real usage, not a bug.
+#    - Destroy idle/abandoned Labs early via /admin (per-cohort "Destroy Labs" after a class
+#      session ends, rather than waiting for the idle reaper's default window)
+#    - If a specific cohort's class just ended, use /admin -> Cohorts -> [cohort] -> Destroy
+#      Cohort Labs immediately rather than waiting
+
+# 3. If pressure is high with FEWER Labs running than capacity-model.js's threshold: something
+#    is consuming more per-Lab resources than the model assumes (a scenario doing something
+#    unusually heavy, a memory leak in a long-running Lab, zombie processes from a crashed
+#    reset). Check per-container usage:
+docker stats --no-stream | grep rootnode-lab-
+
+# 4. Update infra/environments/production/capacity.yml with fresh measured numbers
+#    (infra/scripts/loadtest/) if the per-Lab footprint has genuinely changed, so the
+#    admission-control threshold reflects reality going forward.
+```
+
+Do not silently raise resource limits in `provisioner-config/resource-policy.yaml` to make an
+alert go away without understanding why usage is higher than modeled — that just moves the
+same pressure onto host RAM/CPU directly instead of onto individual Lab limits.

docs/RUNBOOK_NORMAL_DEPLOY.md

@@ -0,0 +1,17 @@
+# Runbook: Normal Deploy
+
+For a routine code change already merged to `main` on the canonical Gitea repo.
+
+1. CI (`infra/ci/gitea-workflows/build-and-test.yml`) runs automatically: tests, image build/tag/push, staging deploy, staging smoke test.
+2. Review the staging smoke test result and, ideally, poke around `https://staging.<domain>` yourself.
+3. Promote to production (manual, deliberate):
+
+```bash
+cd infra/scripts
+./deploy-production.sh sha-<12-char-sha>    # or a release tag, e.g. v1.3.0
+./production-smoke-test.sh
+```
+
+4. Watch Grafana (`/grafana/`) for 10-15 minutes — error rates, Postgres connections, Lab Host
+   memory — before considering the deploy "settled."
+5. If anything looks wrong: `docs/RUNBOOK_ROLLBACK.md`.

docs/RUNBOOK_OWNER_RECOVERY.md

@@ -0,0 +1,27 @@
+# Runbook: Owner Account Recovery
+
+**Locked out with zero working owner accounts** (all deactivated, forgot the only owner's
+password, etc.):
+
+```bash
+ssh rootnode-deploy@rn-platform-01
+docker exec -it rootnode-platform-api-1 sh
+node bootstrap-owner.js [email protected] "Your Name"
+# bootstrap-owner.js refuses to run if an active owner already exists UNLESS the target email
+# belongs to an EXISTING instructor row — in that case it promotes them to owner. Point it at
+# any known instructor email to recover through them, or a brand-new email to create a fresh
+# owner outright if the instructors table itself is in an unknown state.
+```
+
+**Forgot password, account still active and you have SSH access:**
+
+```bash
+docker exec -it rootnode-platform-postgres-1 psql -U rootnode_platform -c \
+  "SELECT instructor_id, email, role, status FROM instructors WHERE role='owner';"
+# Then use another owner's account to reset via /admin -> Instructors -> [account] -> Reset
+# Password, OR re-run bootstrap-owner.js targeting that email (also resets the password).
+```
+
+**Never** hand-edit `password_hash` in the database — it's `scrypt(salt):hash` in a specific
+format (`platform/api/src/auth/password.js`); a malformed value just breaks login rather than
+setting a usable password. Always go through `bootstrap-owner.js` or the admin UI's reset flow.

docs/RUNBOOK_POSTGRES_RESTORE.md

@@ -0,0 +1,45 @@
+# Runbook: Postgres Restore
+
+**When to use:** Postgres corruption/data loss on rn-platform-01, or verifying a backup is
+actually good (do this periodically even without an incident — an untested backup is a
+hypothesis, not a backup).
+
+```bash
+# 1. Find the backup to restore
+ls -la /srv/rootnode-data/backups/    # or wherever backup_offsite_target points, if local copies are gone
+
+# 2. Create a FRESH target database — never restore over the live one directly
+docker exec -it rootnode-platform-postgres-1 psql -U rootnode_platform -c \
+  "CREATE DATABASE rootnode_platform_restore_test;"
+
+# 3. Restore into it
+source /etc/rootnode/backup.env   # for BACKUP_ENCRYPTION_PASSPHRASE
+/opt/rootnode/backup/restore-postgres.sh \
+  /srv/rootnode-data/backups/rootnode-platform-<timestamp>.sql.gz.gpg \
+  "postgres://rootnode_platform:$PGPASS@localhost:5432/rootnode_platform_restore_test"
+# type RESTORE when prompted
+
+# 4. Verify
+/opt/rootnode/backup/verify-restore.sh \
+  "postgres://rootnode_platform:$PGPASS@localhost:5432/rootnode_platform_restore_test"
+
+# 5a. If this was a drill: drop the test database
+docker exec -it rootnode-platform-postgres-1 psql -U rootnode_platform -c \
+  "DROP DATABASE rootnode_platform_restore_test;"
+
+# 5b. If this was a REAL incident: stop the app stack, rename the broken DB, rename the
+#     restored one into its place, restart.
+systemctl stop rootnode-platform
+docker exec -it rootnode-platform-postgres-1 psql -U rootnode_platform -c \
+  "ALTER DATABASE rootnode_platform RENAME TO rootnode_platform_broken_$(date +%s);"
+docker exec -it rootnode-platform-postgres-1 psql -U rootnode_platform -c \
+  "ALTER DATABASE rootnode_platform_restore_test RENAME TO rootnode_platform;"
+systemctl start rootnode-platform
+```
+
+Local, non-production dry run of this exact flow: `infra/backup/test-backup-restore.sh` (uses
+disposable containers, safe to run anytime, no real data involved).
+
+**Recovery point objective:** up to 24 hours of academic data (daily backup cadence) — see
+`docs/BACKUP_DR.md` for the full RPO/RTO discussion and why that's the honest number, not an
+aspirational one.

docs/RUNBOOK_ROLLBACK.md

@@ -0,0 +1,18 @@
+# Runbook: Rollback
+
+```bash
+cd infra/scripts
+./rollback-production.sh              # rolls back to the previous deployed tag automatically
+# or, to go back further than one step:
+./rollback-production.sh sha-<older-sha>
+
+./production-smoke-test.sh
+```
+
+This rolls back **application images only**. If the bad deploy included a database migration
+that needs undoing too, schema changes aren't automatically reversible — see
+`docs/RUNBOOK_FAILED_MIGRATION.md` instead (or in addition).
+
+After rolling back: file an issue / note in the deploy log (`/opt/rootnode/deploy-history.log`
+already has the rollback recorded) about what went wrong before re-attempting the forward
+deploy.

docs/RUNBOOK_STUCK_LAB_CLEANUP.md

@@ -0,0 +1,40 @@
+# Runbook: Stuck Lab Cleanup
+
+A Lab that's stuck `provisioning`/`resetting` past its expected boot window, or a container
+that outlived its Postgres `environments` row (crash during teardown, etc.).
+
+**Via the admin UI (preferred, no host access needed):** `/admin` -> Students -> [student] ->
+Environment -> Destroy, then Provision again if they need a fresh one immediately.
+
+**Via the API directly** (same effect, useful for scripting a batch cleanup):
+```bash
+curl -s -b <owner-session-cookie> -X DELETE https://academy.example.com/api/admin/environments/<environment_id>
+```
+
+**A container the Provisioner itself has lost track of** (rare — e.g. a crash during
+provisioning left an orphaned container/network/firewall chain with no matching `environments`
+row, or vice versa):
+
+```bash
+# On rn-lab-host-01 — list what's actually running
+docker ps -a --format '{{.Names}}\t{{.Status}}' | grep '^rootnode-lab-'
+
+# Cross-reference against the Provisioner's own view
+curl -s http://localhost:4100/environments | jq '.[] | {environment_id, status, container_name}'
+
+# Provisioner already does this automatically on its own restart (reconcileOnStartup,
+# platform/provisioner/src/lifecycle.js) — a simple `systemctl restart rootnode-platform`
+# (which restarts the provisioner container as part of the stack) is often the fastest fix for
+# a batch of orphans rather than hand-cleaning each one.
+
+# Manual last resort — remove the container/network/firewall chain directly:
+docker rm -f rootnode-lab-<id>
+docker network rm rootnode-lab-net-<id>
+iptables -D DOCKER-USER -s <subnet> -j ROOTNODE-ENV-<id>   # remove the jump rule FIRST
+iptables -F ROOTNODE-ENV-<id> && iptables -X ROOTNODE-ENV-<id>
+```
+
+Never manually delete an `environments` row from Postgres directly unless you've confirmed the
+container/network/firewall chain are already gone — the Provisioner treats that table as
+authoritative and will behave unpredictably against real Docker/iptables state it doesn't know
+matches.

docs/RUNBOOK_TLS_RENEWAL.md

@@ -0,0 +1,19 @@
+# Runbook: Public TLS Certificate Renewal
+
+If using Caddy's built-in Let's Encrypt (the default in `infra/docker/platform/Caddyfile.j2`):
+**nothing to do** — Caddy renews automatically well before expiry, as long as port 80 stays
+reachable for the ACME HTTP-01 challenge (`infra/firewall/rn-platform-01.rules` already allows
+it). `infra/scripts/production-smoke-test.sh` checks the live expiry date on every run as an
+early warning if auto-renewal ever silently breaks.
+
+If using Cloudflare origin certs instead (see `docs/PRODUCTION_NETWORK_SECURITY.md` §8 for
+that decision): Cloudflare-issued origin certs are typically 15-year validity — this is a
+once-per-network-topology-change concern, not a recurring one. Re-issue from the Cloudflare
+dashboard (SSL/TLS -> Origin Server) and redeploy the cert/key via the `platform` Ansible role
+if it ever needs replacing (domain change, suspected compromise).
+
+**Manual check:**
+```bash
+echo | openssl s_client -connect academy.example.com:443 -servername academy.example.com 2>/dev/null \
+  | openssl x509 -noout -enddate
+```

docs/RUNBOOK_VM_REBUILD.md

@@ -0,0 +1,31 @@
+# Runbook: Platform VM / Lab Host VM Rebuild
+
+Both VMs are designed to be disposable and rebuildable from code — nothing irreplaceable
+should ever live only on either VM's disk outside of what's backed up (`docs/BACKUP_DR.md`).
+
+## rn-platform-01 lost
+
+Academic data survives (it's in Postgres backups, off-host). Instructor/student accounts and
+progress are recoverable; anything since the last backup is not (`docs/BACKUP_DR.md`'s RPO).
+
+```bash
+cd infra/terraform && terraform apply   # recreates the VM from the template
+cd ../ansible && ansible-playbook site.yml -i inventory/production.ini --limit platform --ask-vault-pass
+# Then restore Postgres — docs/RUNBOOK_POSTGRES_RESTORE.md, step 5b variant (fresh DB this time,
+# no need to rename since it's a fresh instance)
+./infra/scripts/production-smoke-test.sh
+```
+
+## rn-lab-host-01 lost
+
+**No academic data is lost** — this host only ever holds disposable Lab containers by design
+(`docs/BACKUP_DR.md`'s Tier distinction). Every enrolled student's Lab needs re-provisioning
+after this, which is a normal "Prepare Labs" click, not a recovery operation.
+
+```bash
+cd infra/terraform && terraform apply
+cd ../ansible && ansible-playbook site.yml -i inventory/production.ini --limit lab_host --ask-vault-pass
+# Re-generate Docker TLS material for the new host if its identity (IP/DNS) changed —
+# docs/RUNBOOK_DOCKER_TLS_ROTATION.md
+# From /admin: Prepare Labs again for any cohort that needs it.
+```

docs/SECURITY_SCANNING.md

@@ -0,0 +1,47 @@
+# Security Scanning (Phase 4.1 §24)
+
+`infra/ci/gitea-workflows/build-and-test.yml`'s `security-scan` job. All free, open-source,
+no account/signup required for any of them — no paid scanner was added.
+
+## What's scanned
+
+| Tool | Checks | Scope |
+|---|---|---|
+| `npm audit --audit-level=high` | Known-vulnerable dependencies | Every first-party Node service |
+| [gitleaks](https://github.com/gitleaks/gitleaks) | Committed secrets (keys, tokens, credentials) | Whole repo |
+| [hadolint](https://github.com/hadolint/hadolint) | Dockerfile best-practice/security lint | Every first-party Dockerfile |
+| [shellcheck](https://www.shellcheck.net/) | Shell script correctness/security | `infra/**/*.sh` |
+| [trivy](https://github.com/aquasecurity/trivy) | OS/library CVEs in a built container image | `platform-api` image (representative — same base/layers as the other Node services) |
+
+## Severity policy
+
+- **CRITICAL / HIGH** — fails the build (`security-scan` blocks `build-images`, which blocks
+  `deploy-staging`, which blocks production promotion — see the job dependency chain in the
+  workflow file).
+- **MEDIUM / LOW** — reported in the job output, never blocks. A build that's permanently red
+  over a low-severity transitive dependency finding nobody can immediately fix trains everyone
+  to ignore red builds, which is worse than not scanning at all.
+
+`npm audit --audit-level=high` and trivy's `--severity HIGH,CRITICAL` both implement this
+directly at the tool level, not via manual triage.
+
+## What's NOT in the automated job (and why)
+
+- **Dedicated IaC security linting** (checkov/tflint) — not added. `infra/scripts/validate-compose.sh`,
+  `infra/firewall/validate-firewall.sh`, `ansible-playbook --syntax-check`, and `tofu validate`
+  (all in the `regression` job) already catch structural/syntax problems in the infra code;
+  a dedicated security-policy linter for Terraform/Ansible is a reasonable Phase 5 addition once
+  there's a real cloud footprint to misconfigure, not before.
+- **DAST/penetration testing** — out of scope for CI; this is a build-time gate, not a running-system
+  test. Covered separately by `docs/PRODUCTION_VALIDATION_CHECKLIST.md`'s security section once
+  real hardware exists.
+- **SAST beyond hadolint/shellcheck** — the codebase is small enough (a handful of first-party
+  Node services) that `npm audit` + secret scanning + Dockerfile/shell lint cover the realistic
+  risk surface; a dedicated SAST tool (Semgrep, CodeQL) is a reasonable addition once the
+  codebase or team grows enough to justify the added CI time.
+
+## Local reproduction
+
+Every check above can be run locally with the exact same free tools — no CI-only dependency.
+See the `security-scan` job's steps in `infra/ci/gitea-workflows/build-and-test.yml` for the
+exact commands (they're copy-pasteable).

frontend/src/App.jsx

@@ -8,6 +8,7 @@ import ExamTimer from './components/ExamTimer'
 import ExamReport from './components/ExamReport'
 import ExamStartModal from './components/ExamStartModal'
 import ExamHistory from './components/ExamHistory'
+import AssessmentBanner from './components/AssessmentBanner'
 import styles from './App.module.css'
 
 const MIN_SIDEBAR_W = 180
@@ -303,6 +304,7 @@ export default function App() {
   return (
     <div className={styles.app}>
       <Header clusterReady={clusterReady} onShowHistory={() => setShowHistory(true)} />
+      <AssessmentBanner />
 
       {/* Bundle navigation bar */}
       <BundleNav

frontend/src/admin/AccountView.jsx

@@ -0,0 +1,39 @@
+import { useState } from 'react'
+import { adminApi } from './api'
+import styles from './Admin.module.css'
+
+export default function AccountView({ instructor }) {
+  const [oldPassword, setOldPassword] = useState('')
+  const [newPassword, setNewPassword] = useState('')
+  const [error, setError] = useState(null)
+  const [notice, setNotice] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  const submit = async (e) => {
+    e.preventDefault()
+    setBusy(true); setError(null); setNotice(null)
+    try {
+      await adminApi.changePassword(oldPassword, newPassword)
+      setOldPassword(''); setNewPassword('')
+      setNotice('Password changed. Any other sessions you had open elsewhere were signed out.')
+    } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  return (
+    <div className={styles.card}>
+      <h2>Account</h2>
+      <p className={styles.muted}>{instructor.display_name} · {instructor.email} · role: {instructor.role}</p>
+
+      <h3 style={{ marginTop: '1.5rem' }}>Change password</h3>
+      <form onSubmit={submit} className={styles.formRow}>
+        {error && <div className={styles.errorBox}>{error}</div>}
+        <div><label className={styles.label}>Current password</label>
+          <input className={styles.input} type="password" value={oldPassword} onChange={(e) => setOldPassword(e.target.value)} autoComplete="current-password" required /></div>
+        <div><label className={styles.label}>New password (12+ chars)</label>
+          <input className={styles.input} type="password" value={newPassword} onChange={(e) => setNewPassword(e.target.value)} autoComplete="new-password" minLength={12} required /></div>
+        <div><button className={styles.btn} disabled={busy}>{busy ? 'Changing…' : 'Change password'}</button></div>
+      </form>
+      {notice && <p className={styles.muted}>{notice}</p>}
+    </div>
+  )
+}

frontend/src/admin/Admin.module.css

@@ -0,0 +1,62 @@
+/* Admin portal — visually distinct from the student shell (a muted accent instead of
+   --green) so instructors and students never mistake which mode they're in, while still
+   reusing the same design tokens for everything else. */
+
+.wrap { min-height: 100vh; background: var(--bg); color: var(--text); font-family: var(--sans); }
+
+.loginWrap { height: 100vh; display: flex; align-items: center; justify-content: center; }
+.loginCard { width: 360px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 2rem; }
+
+.brand { font-family: var(--mono); font-size: 1.2rem; font-weight: 600; color: var(--blue); display: flex; align-items: center; gap: 0.5rem; }
+.subtitle { color: var(--text-2); font-size: 0.85rem; margin: 0.4rem 0 1.25rem; }
+
+.input, .select {
+  width: 100%; padding: 0.55rem 0.6rem; margin-top: 0.3rem;
+  background: var(--surface2); border: 1px solid var(--border2); border-radius: var(--radius);
+  color: var(--text); font-family: var(--sans); font-size: 0.9rem;
+}
+.label { display: block; font-size: 0.8rem; color: var(--text-2); margin-top: 0.9rem; }
+
+.btn {
+  padding: 0.55rem 0.9rem; background: var(--blue); color: #04141c; border: none;
+  border-radius: var(--radius); font-weight: 600; font-size: 0.85rem; cursor: pointer;
+}
+.btn:disabled { opacity: 0.5; cursor: not-allowed; }
+.btnSecondary { padding: 0.5rem 0.8rem; background: transparent; color: var(--text); border: 1px solid var(--border2); border-radius: var(--radius); font-size: 0.85rem; cursor: pointer; }
+.btnDanger { padding: 0.5rem 0.8rem; background: transparent; color: var(--red); border: 1px solid var(--red); border-radius: var(--radius); font-size: 0.85rem; cursor: pointer; }
+
+.header { display: flex; align-items: center; justify-content: space-between; padding: 1rem 2rem; border-bottom: 1px solid var(--border); }
+.nav { display: flex; gap: 1.25rem; }
+.navLink { color: var(--text-2); cursor: pointer; font-size: 0.9rem; background: none; border: none; padding: 0.3rem 0; }
+.navLinkActive { color: var(--blue); border-bottom: 2px solid var(--blue); }
+
+.content { max-width: 1000px; margin: 1.5rem auto; padding: 0 1.5rem; }
+
+.statGrid { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 0.75rem; margin-bottom: 1.5rem; }
+.statCard { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 1rem; }
+.statValue { font-size: 1.6rem; font-weight: 700; }
+.statLabel { color: var(--text-2); font-size: 0.78rem; margin-top: 0.2rem; }
+
+.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 1.25rem; margin-bottom: 1.25rem; }
+.card h2, .card h3 { margin-bottom: 0.75rem; font-size: 1rem; }
+
+table { width: 100%; border-collapse: collapse; font-size: 0.85rem; }
+th { text-align: left; color: var(--text-2); font-weight: 600; padding: 0.4rem 0.6rem; border-bottom: 1px solid var(--border2); font-size: 0.75rem; text-transform: uppercase; }
+td { padding: 0.5rem 0.6rem; border-bottom: 1px solid var(--border); }
+tr:hover td { background: var(--surface2); }
+
+.pill { display: inline-block; padding: 0.15rem 0.55rem; border-radius: 999px; font-size: 0.75rem; font-family: var(--mono); }
+.pillOk { background: var(--green-dim); color: var(--green); }
+.pillWarn { background: var(--amber-dim); color: var(--amber); }
+.pillErr { background: var(--red-dim); color: var(--red); }
+.pillMuted { background: var(--surface3); color: var(--text-2); }
+
+.formRow { display: flex; gap: 0.5rem; align-items: end; margin-bottom: 1rem; flex-wrap: wrap; }
+.formRow > div { flex: 1; min-width: 140px; }
+
+.linkBtn { background: none; border: none; color: var(--blue); cursor: pointer; font-size: 0.85rem; padding: 0; text-decoration: underline; }
+.errorBox { background: var(--red-dim); color: var(--red); border: 1px solid var(--red); border-radius: var(--radius); padding: 0.6rem 0.8rem; font-size: 0.85rem; margin-bottom: 1rem; }
+.muted { color: var(--text-2); font-size: 0.85rem; }
+
+/* Phase 4.1 §16 — shared pagination control (AuditView, StudentsView attempts). */
+.pager { display: flex; align-items: center; gap: 0.75rem; margin-top: 0.75rem; }

frontend/src/admin/AdminDashboard.jsx

@@ -0,0 +1,68 @@
+import { useState, useEffect } from 'react'
+import { adminApi } from './api'
+import styles from './Admin.module.css'
+
+// Operational overview — active cohorts, students, Lab states, recent activity. Deliberately
+// lean (no Prometheus/Grafana here, see docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md §9) — this is
+// "is class ready / is anything on fire," not a metrics platform.
+export default function AdminDashboard() {
+  const [data, setData] = useState(null)
+  const [error, setError] = useState(null)
+
+  useEffect(() => {
+    adminApi.dashboard().then(setData).catch((e) => setError(e.message))
+  }, [])
+
+  if (error) return <div className={styles.errorBox}>{error}</div>
+  if (!data) return <p className={styles.muted}>Loading…</p>
+
+  return (
+    <>
+      <div className={styles.statGrid}>
+        <Stat label="Active cohorts" value={data.active_cohorts} />
+        <Stat label="Total students" value={data.total_students} />
+        <Stat label="Labs running" value={data.labs.running} />
+        <Stat label="Labs provisioning" value={data.labs.provisioning} />
+        <Stat label="Labs in error" value={data.labs.error} />
+        <Stat label="Labs idle/destroyed" value={data.labs.idle_or_destroyed} />
+      </div>
+
+      <div className={styles.card}>
+        <h3>Recent completions</h3>
+        {data.recent_completions.length === 0 ? <p className={styles.muted}>None yet.</p> : (
+          <table>
+            <thead><tr><th>Student</th><th>Scenario</th><th>Completed</th></tr></thead>
+            <tbody>
+              {data.recent_completions.map((c, i) => (
+                <tr key={i}><td>{c.display_name}</td><td>{c.scenario_id}</td><td>{new Date(c.completed_at).toLocaleString()}</td></tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+
+      <div className={styles.card}>
+        <h3>Recent environment failures</h3>
+        {data.recent_failures.length === 0 ? <p className={styles.muted}>None.</p> : (
+          <table>
+            <thead><tr><th>Student</th><th>Reason</th><th>When</th></tr></thead>
+            <tbody>
+              {data.recent_failures.map((f, i) => (
+                <tr key={i}><td>{f.student_id}</td><td>{f.error_reason || '—'}</td><td>{f.started_at ? new Date(f.started_at).toLocaleString() : '—'}</td></tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+    </>
+  )
+}
+
+function Stat({ label, value }) {
+  return (
+    <div className={styles.statCard}>
+      <div className={styles.statValue}>{value}</div>
+      <div className={styles.statLabel}>{label}</div>
+    </div>
+  )
+}

frontend/src/admin/AdminPortal.jsx

@@ -0,0 +1,107 @@
+import { useState, useEffect } from 'react'
+import { adminApi } from './api'
+import AdminDashboard from './AdminDashboard'
+import CohortsView from './CohortsView'
+import StudentsView from './StudentsView'
+import InstructorsView from './InstructorsView'
+import AuditView from './AuditView'
+import AccountView from './AccountView'
+import LearningView from './LearningView'
+import AssessmentsView from './AssessmentsView'
+import styles from './Admin.module.css'
+
+// Instructor/Admin portal — clearly separate from the student experience (/admin route,
+// separate rn_instructor session cookie, separate login). A student session cannot reach any
+// of these views or their underlying /api/admin/* routes. Per-person accounts replace Phase
+// 2B's single shared ADMIN_PASSWORD — see docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md.
+// Learning/Assessments (Phase 3B) are visible to every instructor role — cohort scoping for a
+// plain 'instructor' happens server-side per route, not by hiding the whole tab.
+const NAV = [
+  { key: 'dashboard', label: 'Dashboard' },
+  { key: 'cohorts', label: 'Cohorts' },
+  { key: 'students', label: 'Students' },
+  { key: 'learning', label: 'Learning' },
+  { key: 'assessments', label: 'Assessments' },
+  { key: 'instructors', label: 'Instructors', roles: ['owner'] },
+  { key: 'audit', label: 'Audit', roles: ['owner', 'admin'] },
+]
+
+export default function AdminPortal() {
+  const [instructor, setInstructor] = useState(null) // null = checking, false = need login, object = signed in
+  const [view, setView] = useState('dashboard')
+
+  useEffect(() => {
+    adminApi.session().then((r) => setInstructor(r.instructor)).catch(() => setInstructor(false))
+  }, [])
+
+  if (instructor === null) return null
+  if (!instructor) return <InstructorLogin onLogin={setInstructor} />
+
+  const visibleNav = NAV.filter((item) => !item.roles || item.roles.includes(instructor.role))
+
+  return (
+    <div className={styles.wrap}>
+      <header className={styles.header}>
+        <div className={styles.brand}>⚙ RootNode Admin</div>
+        <nav className={styles.nav}>
+          {visibleNav.map((item) => (
+            <button key={item.key} className={`${styles.navLink} ${view === item.key ? styles.navLinkActive : ''}`} onClick={() => setView(item.key)}>
+              {item.label}
+            </button>
+          ))}
+          <button className={`${styles.navLink} ${view === 'account' ? styles.navLinkActive : ''}`} onClick={() => setView('account')}>
+            {instructor.display_name}
+          </button>
+          <button className={styles.navLink} onClick={() => adminApi.logout().then(() => setInstructor(false))}>Sign out</button>
+        </nav>
+      </header>
+      <div className={styles.content}>
+        {view === 'dashboard' && <AdminDashboard />}
+        {view === 'cohorts' && <CohortsView role={instructor.role} />}
+        {view === 'students' && <StudentsView role={instructor.role} />}
+        {view === 'learning' && <LearningView />}
+        {view === 'assessments' && <AssessmentsView role={instructor.role} />}
+        {view === 'instructors' && instructor.role === 'owner' && <InstructorsView currentInstructorId={instructor.instructor_id} />}
+        {view === 'audit' && ['owner', 'admin'].includes(instructor.role) && <AuditView />}
+        {view === 'account' && <AccountView instructor={instructor} />}
+      </div>
+    </div>
+  )
+}
+
+function InstructorLogin({ onLogin }) {
+  const [email, setEmail] = useState('')
+  const [password, setPassword] = useState('')
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  const submit = async (e) => {
+    e.preventDefault()
+    setBusy(true); setError(null)
+    try {
+      const { instructor } = await adminApi.login(email, password)
+      onLogin(instructor)
+    } catch (e) {
+      setError(e.message || 'Sign-in failed.')
+    } finally {
+      setBusy(false)
+    }
+  }
+
+  return (
+    <div className={styles.loginWrap}>
+      <form className={styles.loginCard} onSubmit={submit}>
+        <div className={styles.brand}>⚙ RootNode Admin</div>
+        <p className={styles.subtitle}>Instructor sign-in. Not connected to student accounts.</p>
+        {error && <div className={styles.errorBox}>{error}</div>}
+        <label className={styles.label}>Email</label>
+        <input className={styles.input} type="email" value={email} onChange={(e) => setEmail(e.target.value)} autoFocus autoComplete="username" />
+        <label className={styles.label} style={{ marginTop: '0.75rem' }}>Password</label>
+        <input className={styles.input} type="password" value={password} onChange={(e) => setPassword(e.target.value)} autoComplete="current-password" />
+        <button className={styles.btn} style={{ marginTop: '1.25rem', width: '100%' }} disabled={busy || !email || !password}>
+          {busy ? 'Signing in…' : 'Sign in'}
+        </button>
+      </form>
+    </div>
+  )
+}

frontend/src/admin/AssessmentsView.jsx

@@ -0,0 +1,258 @@
+import { useState, useEffect, useCallback } from 'react'
+import { adminApi } from './api'
+import styles from './Admin.module.css'
+
+// Exam and Capstone definition/session management. Definition authoring (create/edit) is
+// admin/owner only server-side (RBAC) — a plain instructor can still assign an existing
+// definition to their own cohort and view/cancel sessions within it, so the form below is
+// always shown but the server will 403 a create/edit attempt from an instructor role; this
+// mirrors CohortsView's approach of not pre-emptively hiding every control, since assessments
+// are viewed by all roles and only definition-authoring is restricted.
+export default function AssessmentsView({ role }) {
+  const [assessments, setAssessments] = useState(null)
+  const [cohorts, setCohorts] = useState(null)
+  const [selected, setSelected] = useState(null)
+  const [error, setError] = useState(null)
+  const canAuthor = role === 'owner' || role === 'admin'
+
+  const reload = useCallback(() => {
+    adminApi.assessments().then(setAssessments).catch((e) => setError(e.message))
+    adminApi.cohorts().then(setCohorts).catch(() => {})
+  }, [])
+  useEffect(reload, [reload])
+
+  if (selected) return <AssessmentDetail definition={selected} cohorts={cohorts} onBack={() => { setSelected(null); reload() }} />
+
+  return (
+    <>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      {canAuthor && (
+        <div className={styles.card}>
+          <h2>Create assessment</h2>
+          <CreateAssessmentForm onCreated={reload} role={role} />
+        </div>
+      )}
+      <div className={styles.card}>
+        <h2>Exams &amp; Capstones</h2>
+        {!assessments ? <p className={styles.muted}>Loading…</p> : (
+          <table>
+            <thead><tr><th>Title</th><th>Type</th><th>Duration</th><th>Hints</th><th>Status</th><th /></tr></thead>
+            <tbody>
+              {assessments.map((a) => (
+                <tr key={a.assessment_definition_id}>
+                  <td>{a.title}</td>
+                  <td><span className={styles.pill}>{a.type}</span></td>
+                  <td>{a.duration_minutes} min</td>
+                  <td>{a.hint_policy}</td>
+                  <td><span className={`${styles.pill} ${a.status === 'active' ? styles.pillOk : styles.pillMuted}`}>{a.status}</span></td>
+                  <td><button className={styles.linkBtn} onClick={() => setSelected(a)}>Open</button></td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+    </>
+  )
+}
+
+// Phase 4.1 §18 — pool_spec is built from structured picks (required scenarios + named random
+// pools), not hand-typed JSON. `catalog` ({ stages: [{ id, name, scenarios: [{id,title}] }] })
+// comes from GET /api/admin/scenario-catalog. An owner can still drop into a raw-JSON view for
+// anything the structured editor doesn't cover — see the toggle below.
+function PoolSpecEditor({ catalog, required, setRequired, pools, setPools }) {
+  const allScenarios = (catalog?.stages || []).flatMap((s) => s.scenarios.map((sc) => ({ ...sc, stageName: s.name })))
+  const titleFor = (id) => allScenarios.find((s) => s.id === id)?.title || id
+
+  const addPool = () => setPools([...pools, { count: 1, from: [] }])
+  const removePool = (i) => setPools(pools.filter((_, idx) => idx !== i))
+  const updatePool = (i, patch) => setPools(pools.map((p, idx) => (idx === i ? { ...p, ...patch } : p)))
+
+  return (
+    <div>
+      <label className={styles.label}>Required scenarios (always included)</label>
+      <select className={styles.select} multiple size={6} style={{ width: '100%' }}
+        value={required} onChange={(e) => setRequired([...e.target.selectedOptions].map((o) => o.value))}>
+        {catalog?.stages.map((stage) => (
+          <optgroup key={stage.id} label={stage.name}>
+            {stage.scenarios.map((sc) => <option key={sc.id} value={sc.id}>{sc.title}</option>)}
+          </optgroup>
+        ))}
+      </select>
+      <p className={styles.muted}>{required.length ? `${required.length} selected: ${required.map(titleFor).join(', ')}` : 'None selected — cmd/ctrl-click to pick multiple.'}</p>
+
+      <label className={styles.label} style={{ marginTop: '1rem', display: 'block' }}>Random pools (draw N at random from a set, every attempt)</label>
+      {pools.map((pool, i) => (
+        <div key={i} className={styles.card} style={{ marginBottom: '0.5rem' }}>
+          <div className={styles.formRow}>
+            <div style={{ maxWidth: '100px' }}><label className={styles.label}>Draw count</label>
+              <input className={styles.input} type="number" min="1" value={pool.count}
+                onChange={(e) => updatePool(i, { count: Number(e.target.value) })} /></div>
+            <div><button type="button" className={styles.linkBtn} onClick={() => removePool(i)}>Remove pool</button></div>
+          </div>
+          <label className={styles.label}>Draw from</label>
+          <select className={styles.select} multiple size={5} style={{ width: '100%' }}
+            value={pool.from} onChange={(e) => updatePool(i, { from: [...e.target.selectedOptions].map((o) => o.value) })}>
+            {catalog?.stages.map((stage) => (
+              <optgroup key={stage.id} label={stage.name}>
+                {stage.scenarios.map((sc) => <option key={sc.id} value={sc.id}>{sc.title}</option>)}
+              </optgroup>
+            ))}
+          </select>
+          {pool.count > pool.from.length && <p className={styles.muted} style={{ color: 'var(--amber, #b58900)' }}>Draw count ({pool.count}) exceeds the pool size ({pool.from.length}) — every draw will use every scenario, not a random subset.</p>}
+        </div>
+      ))}
+      <button type="button" className={styles.linkBtn} onClick={addPool}>+ Add random pool</button>
+    </div>
+  )
+}
+
+function CreateAssessmentForm({ onCreated, role }) {
+  const [form, setForm] = useState({ id: '', type: 'exam', title: '', duration_minutes: 60, hint_policy: 'disabled' })
+  const [catalog, setCatalog] = useState(null)
+  const [required, setRequired] = useState([])
+  const [pools, setPools] = useState([])
+  const [advanced, setAdvanced] = useState(false)
+  const [rawPoolSpec, setRawPoolSpec] = useState('')
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  useEffect(() => { adminApi.scenarioCatalog().then(setCatalog).catch((e) => setError(e.message)) }, [])
+
+  const submit = async (e) => {
+    e.preventDefault()
+    setBusy(true); setError(null)
+    try {
+      // Owner's raw-JSON view, when open, is the source of truth — otherwise built from the
+      // structured pickers above.
+      const pool_spec = advanced
+        ? JSON.parse(rawPoolSpec || '{"required":[],"random":[]}')
+        : { required, random: pools.filter((p) => p.count > 0 && p.from.length > 0) };
+      if (!advanced && !required.length && !pool_spec.random.length) {
+        throw new Error('Pick at least one required scenario or one random pool.')
+      }
+      await adminApi.createAssessment({ ...form, duration_minutes: Number(form.duration_minutes), pool_spec })
+      setForm({ id: '', type: 'exam', title: '', duration_minutes: 60, hint_policy: 'disabled' })
+      setRequired([]); setPools([]); setRawPoolSpec('')
+      onCreated()
+    } catch (e) { setError(e.message?.includes('JSON') ? 'Raw pool_spec must be valid JSON' : e.message) } finally { setBusy(false) }
+  }
+
+  return (
+    <form onSubmit={submit}>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      <div className={styles.formRow}>
+        <div><label className={styles.label}>ID (slug)</label>
+          <input className={styles.input} value={form.id} onChange={(e) => setForm({ ...form, id: e.target.value })} required /></div>
+        <div><label className={styles.label}>Title</label>
+          <input className={styles.input} value={form.title} onChange={(e) => setForm({ ...form, title: e.target.value })} required /></div>
+        <div><label className={styles.label}>Type</label>
+          <select className={styles.select} value={form.type} onChange={(e) => setForm({ ...form, type: e.target.value })}>
+            <option value="exam">exam</option><option value="capstone">capstone</option>
+          </select></div>
+        <div><label className={styles.label}>Duration (min)</label>
+          <input className={styles.input} type="number" value={form.duration_minutes} onChange={(e) => setForm({ ...form, duration_minutes: e.target.value })} required /></div>
+        <div><label className={styles.label}>Hint policy</label>
+          <select className={styles.select} value={form.hint_policy} onChange={(e) => setForm({ ...form, hint_policy: e.target.value })}>
+            <option value="disabled">disabled</option><option value="flagged">flagged</option><option value="free">free</option>
+          </select></div>
+      </div>
+
+      {role === 'owner' && (
+        <p className={styles.muted}>
+          <button type="button" className={styles.linkBtn} onClick={() => setAdvanced(!advanced)}>
+            {advanced ? '← Back to the structured editor' : 'Advanced: edit pool_spec as raw JSON →'}
+          </button>
+        </p>
+      )}
+
+      {advanced ? (
+        <>
+          <label className={styles.label}>Pool spec (JSON)</label>
+          <textarea className={styles.input} style={{ width: '100%', fontFamily: 'var(--mono)', minHeight: '4rem' }}
+            placeholder='{"required":["scenario-id"],"random":[{"count":1,"from":["a","b"]}]}'
+            value={rawPoolSpec} onChange={(e) => setRawPoolSpec(e.target.value)} required />
+        </>
+      ) : !catalog ? <p className={styles.muted}>Loading scenario catalog…</p> : (
+        <PoolSpecEditor catalog={catalog} required={required} setRequired={setRequired} pools={pools} setPools={setPools} />
+      )}
+
+      <button className={styles.btn} style={{ marginTop: '0.75rem' }} disabled={busy}>{busy ? 'Creating…' : 'Create'}</button>
+    </form>
+  )
+}
+
+function AssessmentDetail({ definition, cohorts, onBack }) {
+  // Phase 4.1 §16 — assessmentSessions is now paginated (was unbounded); `result` holds the
+  // full { items, page, total, total_pages } envelope, `sessions` stays the plain array for
+  // the table below so its render logic doesn't need to change.
+  const [result, setResult] = useState(null)
+  const [page, setPage] = useState(1)
+  const [error, setError] = useState(null)
+  const [notice, setNotice] = useState(null)
+  const [cohortId, setCohortId] = useState(cohorts?.[0]?.cohort_id || '')
+  const [busy, setBusy] = useState(false)
+
+  const reload = useCallback(() => {
+    adminApi.assessmentSessions(definition.assessment_definition_id, page).then(setResult).catch((e) => setError(e.message))
+  }, [definition, page])
+  useEffect(reload, [reload])
+  const sessions = result?.items || null
+
+  const assign = async () => {
+    setBusy(true); setError(null); setNotice(null)
+    try { await adminApi.assignAssessment(definition.assessment_definition_id, cohortId); setNotice('Assigned.') }
+    catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const cancelSession = async (sessionId) => {
+    if (!window.confirm('Cancel this session?')) return
+    try { await adminApi.cancelAssessmentSession(sessionId); reload() } catch (e) { setError(e.message) }
+  }
+
+  return (
+    <>
+      <button className={styles.linkBtn} onClick={onBack}>&larr; Back to assessments</button>
+      <h2 style={{ margin: '1rem 0' }}>{definition.title} <span className={styles.muted}>({definition.type})</span></h2>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      {notice && <p className={styles.muted}>{notice}</p>}
+
+      <div className={styles.card}>
+        <h3>Assign to cohort</h3>
+        <div className={styles.formRow}>
+          <div><select className={styles.select} value={cohortId} onChange={(e) => setCohortId(e.target.value)}>
+            {cohorts?.map((c) => <option key={c.cohort_id} value={c.cohort_id}>{c.name}</option>)}
+          </select></div>
+          <div><button className={styles.btn} disabled={busy || !cohortId} onClick={assign}>Assign</button></div>
+        </div>
+      </div>
+
+      <div className={styles.card}>
+        <h3>Sessions</h3>
+        {!sessions ? <p className={styles.muted}>Loading…</p> : sessions.length === 0 ? <p className={styles.muted}>None yet.</p> : (
+          <table>
+            <thead><tr><th>Student</th><th>Status</th><th>Started</th><th>Result</th><th /></tr></thead>
+            <tbody>
+              {sessions.map((s) => (
+                <tr key={s.assessment_session_id}>
+                  <td>{s.display_name}</td>
+                  <td><span className={`${styles.pill} ${s.status === 'completed' ? styles.pillOk : s.status === 'expired' ? styles.pillErr : styles.pillWarn}`}>{s.status}</span></td>
+                  <td>{s.started_at ? new Date(s.started_at).toLocaleString() : '—'}</td>
+                  <td>{s.result ? `${s.result.scenarios_passed}/${s.result.scenarios_total}` : '—'}</td>
+                  <td>{['not_started', 'in_progress'].includes(s.status) && <button className={styles.linkBtn} onClick={() => cancelSession(s.assessment_session_id)}>Cancel</button>}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+        {result && result.total_pages > 1 && (
+          <div className={styles.pager}>
+            <button disabled={page <= 1} onClick={() => setPage((p) => p - 1)}>Previous</button>
+            <span className={styles.muted}>Page {result.page} of {result.total_pages} ({result.total} total)</span>
+            <button disabled={page >= result.total_pages} onClick={() => setPage((p) => p + 1)}>Next</button>
+          </div>
+        )}
+      </div>
+    </>
+  )
+}

frontend/src/admin/AuditView.jsx

@@ -0,0 +1,49 @@
+import { useState, useEffect } from 'react'
+import { adminApi } from './api'
+import styles from './Admin.module.css'
+
+// admin/owner only (enforced server-side too). Phase 4.1 §16 — real server-side pagination
+// (platform/api/src/pagination.js) replaces the old flat "latest 200, nothing older" cap.
+export default function AuditView() {
+  const [page, setPage] = useState(1)
+  const [result, setResult] = useState(null)
+  const [error, setError] = useState(null)
+
+  useEffect(() => {
+    setResult(null)
+    adminApi.auditEvents(page).then(setResult).catch((e) => setError(e.message))
+  }, [page])
+
+  const events = result?.items || []
+
+  return (
+    <div className={styles.card}>
+      <h2>Audit log</h2>
+      <p className={styles.muted}>{result ? `${result.total} total events` : 'Security/admin events, most recent first.'}</p>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      {!result ? <p className={styles.muted}>Loading…</p> : (
+        <>
+          <table>
+            <thead><tr><th>When</th><th>Actor</th><th>Action</th><th>Resource</th><th>Result</th></tr></thead>
+            <tbody>
+              {events.map((e) => (
+                <tr key={e.audit_event_id}>
+                  <td>{new Date(e.created_at).toLocaleString()}</td>
+                  <td>{e.actor_type}{e.actor_id ? ` · ${e.actor_id.slice(0, 8)}` : ''}</td>
+                  <td>{e.action}</td>
+                  <td>{e.resource_type ? `${e.resource_type}${e.resource_id ? ` (${e.resource_id})` : ''}` : '—'}</td>
+                  <td><span className={`${styles.pill} ${e.result === 'success' ? styles.pillOk : styles.pillErr}`}>{e.result}</span></td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+          <div className={styles.pager}>
+            <button disabled={page <= 1} onClick={() => setPage((p) => p - 1)}>Previous</button>
+            <span className={styles.muted}>Page {result.page} of {result.total_pages}</span>
+            <button disabled={page >= result.total_pages} onClick={() => setPage((p) => p + 1)}>Next</button>
+          </div>
+        </>
+      )}
+    </div>
+  )
+}

frontend/src/admin/CohortsView.jsx

@@ -0,0 +1,221 @@
+import { useState, useEffect, useCallback } from 'react'
+import { adminApi } from './api'
+import styles from './Admin.module.css'
+
+export default function CohortsView({ role }) {
+  const [cohorts, setCohorts] = useState(null)
+  const [selected, setSelected] = useState(null)
+  const [error, setError] = useState(null)
+  const canManage = role !== 'instructor' // owner/admin only — a plain instructor works within cohorts already assigned to them
+
+  const reload = useCallback(() => {
+    adminApi.cohorts().then(setCohorts).catch((e) => setError(e.message))
+  }, [])
+  useEffect(reload, [reload])
+
+  if (selected) return <CohortDetail cohortId={selected} canManage={canManage} onBack={() => { setSelected(null); reload() }} />
+
+  return (
+    <>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      {canManage && (
+        <div className={styles.card}>
+          <h2>Create cohort</h2>
+          <CreateCohortForm onCreated={reload} />
+        </div>
+      )}
+      <div className={styles.card}>
+        <h2>Cohorts</h2>
+        {!cohorts ? <p className={styles.muted}>Loading…</p> : cohorts.length === 0 ? <p className={styles.muted}>None yet.</p> : (
+          <table>
+            <thead><tr><th>Name</th><th>Tier</th><th>Students</th><th>Status</th><th /></tr></thead>
+            <tbody>
+              {cohorts.map((c) => (
+                <tr key={c.cohort_id}>
+                  <td>{c.name}</td>
+                  <td>{c.tier || '—'}</td>
+                  <td>{c.student_count}</td>
+                  <td><span className={`${styles.pill} ${c.status === 'active' ? styles.pillOk : styles.pillMuted}`}>{c.status}</span></td>
+                  <td><button className={styles.linkBtn} onClick={() => setSelected(c.cohort_id)}>Open</button></td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+    </>
+  )
+}
+
+function CreateCohortForm({ onCreated }) {
+  const [form, setForm] = useState({ cohort_id: '', name: '', tier: '', start_date: '', end_date: '' })
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  const submit = async (e) => {
+    e.preventDefault()
+    setBusy(true); setError(null)
+    try {
+      await adminApi.createCohort(form)
+      setForm({ cohort_id: '', name: '', tier: '', start_date: '', end_date: '' })
+      onCreated()
+    } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  return (
+    <form onSubmit={submit}>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      <div className={styles.formRow}>
+        <div><label className={styles.label}>Cohort ID (slug)</label>
+          <input className={styles.input} placeholder="root-fall-2026" value={form.cohort_id} onChange={(e) => setForm({ ...form, cohort_id: e.target.value })} required /></div>
+        <div><label className={styles.label}>Name</label>
+          <input className={styles.input} placeholder="Root Fall 2026" value={form.name} onChange={(e) => setForm({ ...form, name: e.target.value })} required /></div>
+        <div><label className={styles.label}>Tier</label>
+          <input className={styles.input} placeholder="root" value={form.tier} onChange={(e) => setForm({ ...form, tier: e.target.value })} /></div>
+        <div><label className={styles.label}>Start date</label>
+          <input className={styles.input} type="date" value={form.start_date} onChange={(e) => setForm({ ...form, start_date: e.target.value })} /></div>
+        <div><label className={styles.label}>End date</label>
+          <input className={styles.input} type="date" value={form.end_date} onChange={(e) => setForm({ ...form, end_date: e.target.value })} /></div>
+        <div><button className={styles.btn} disabled={busy}>{busy ? 'Creating…' : 'Create cohort'}</button></div>
+      </div>
+    </form>
+  )
+}
+
+function CohortDetail({ cohortId, canManage, onBack }) {
+  const [students, setStudents] = useState(null)
+  const [progress, setProgress] = useState(null)
+  const [prepResults, setPrepResults] = useState(null)
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+  const [newStudentName, setNewStudentName] = useState('')
+
+  const reload = useCallback(() => {
+    adminApi.cohortStudents(cohortId).then(setStudents).catch((e) => setError(e.message))
+    adminApi.cohortProgress(cohortId).then(setProgress).catch(() => {})
+  }, [cohortId])
+  useEffect(reload, [reload])
+
+  const addStudent = async (e) => {
+    e.preventDefault()
+    if (!newStudentName.trim()) return
+    setBusy(true); setError(null)
+    try {
+      await adminApi.createStudent(newStudentName.trim(), cohortId)
+      setNewStudentName('')
+      reload()
+    } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const prepareLabs = async () => {
+    setBusy(true); setError(null); setPrepResults(null)
+    try {
+      const { results } = await adminApi.prepareLabs(cohortId)
+      setPrepResults(results)
+    } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const destroyLabs = async () => {
+    if (!window.confirm(`Destroy all Labs for this cohort? Academic progress is not affected.`)) return
+    setBusy(true); setError(null)
+    try {
+      const { results } = await adminApi.destroyLabs(cohortId)
+      setPrepResults(results)
+    } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const assignCurriculum = async () => {
+    setBusy(true)
+    try { await adminApi.assignCohortCurriculum(cohortId, 'rootnode-path') } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const readyCount = prepResults?.filter((r) => r.status === 'running').length
+
+  return (
+    <>
+      <button className={styles.linkBtn} onClick={onBack}>&larr; Back to cohorts</button>
+      <h2 style={{ margin: '1rem 0' }}>{cohortId}</h2>
+      {error && <div className={styles.errorBox}>{error}</div>}
+
+      <div className={styles.card}>
+        <h3>Roster ({students?.length ?? '…'})</h3>
+        {canManage && (
+          <form onSubmit={addStudent} className={styles.formRow}>
+            <div><input className={styles.input} placeholder="New student name" value={newStudentName} onChange={(e) => setNewStudentName(e.target.value)} /></div>
+            <div><button className={styles.btn} disabled={busy}>Add student</button></div>
+          </form>
+        )}
+        {students && (
+          <table>
+            <thead><tr><th>Name</th><th>Status</th><th>Last active</th></tr></thead>
+            <tbody>
+              {students.map((s) => (
+                <tr key={s.student_id}>
+                  <td>{s.display_name}</td>
+                  <td><span className={`${styles.pill} ${s.status === 'active' ? styles.pillOk : styles.pillMuted}`}>{s.status}</span></td>
+                  <td>{s.last_active_at ? new Date(s.last_active_at).toLocaleString() : 'never'}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+
+      {canManage && (
+        <div className={styles.card}>
+          <h3>Curriculum</h3>
+          <p className={styles.muted}>RootNode Learning Path (Foundation → Workloads → Networking → Configuration → Troubleshooting → Real Ops → Capstone)</p>
+          <button className={styles.btnSecondary} onClick={assignCurriculum} disabled={busy}>Assign RootNode Path to cohort</button>
+        </div>
+      )}
+
+      {progress && (
+        <div className={styles.card}>
+          <h3>Cohort progress ({progress.student_count} students)</h3>
+          {progress.stages.map((s) => (
+            <div key={s.id} style={{ marginBottom: '0.5rem' }}>
+              <div style={{ display: 'flex', justifyContent: 'space-between', fontSize: '0.85rem' }}>
+                <span>{s.name}</span><span className={styles.muted}>{s.pct}%</span>
+              </div>
+              <div style={{ background: 'var(--surface3)', borderRadius: 4, height: 6 }}>
+                <div style={{ background: 'var(--green)', borderRadius: 4, height: 6, width: `${s.pct}%` }} />
+              </div>
+            </div>
+          ))}
+        </div>
+      )}
+
+      <div className={styles.card}>
+        <h3>Classroom preparation</h3>
+        <div className={styles.formRow}>
+          <button className={styles.btn} onClick={prepareLabs} disabled={busy}>{busy ? 'Working…' : 'Prepare Labs'}</button>
+          <button className={styles.btnDanger} onClick={destroyLabs} disabled={busy}>Destroy Cohort Labs</button>
+        </div>
+        {prepResults && (
+          <>
+            {readyCount !== undefined && <p className={styles.muted}>{readyCount}/{prepResults.length} READY</p>}
+            <table>
+              <thead><tr><th>Student</th><th>Status</th></tr></thead>
+              <tbody>
+                {prepResults.map((r) => (
+                  <tr key={r.student_id}>
+                    <td>{r.display_name || r.student_id}</td>
+                    <td><StatusPill status={r.status} /></td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </>
+        )}
+      </div>
+    </>
+  )
+}
+
+export function StatusPill({ status }) {
+  const cls = status === 'running' ? styles.pillOk
+    : status === 'error' ? styles.pillErr
+    : ['provisioning', 'requested', 'resetting'].includes(status) ? styles.pillWarn
+    : styles.pillMuted
+  return <span className={`${styles.pill} ${cls}`}>{status}</span>
+}

frontend/src/admin/InstructorsView.jsx

@@ -0,0 +1,180 @@
+import { useState, useEffect, useCallback } from 'react'
+import { adminApi } from './api'
+import styles from './Admin.module.css'
+
+// Owner-only — the server enforces this too (requireOwner on every /api/admin/instructors*
+// route); this component is only ever mounted for an owner, but the backend never trusts that.
+export default function InstructorsView({ currentInstructorId }) {
+  const [instructors, setInstructors] = useState(null)
+  const [selected, setSelected] = useState(null)
+  const [error, setError] = useState(null)
+
+  const reload = useCallback(() => {
+    adminApi.instructors().then(setInstructors).catch((e) => setError(e.message))
+  }, [])
+  useEffect(reload, [reload])
+
+  if (selected) return <InstructorDetail instructorId={selected} isSelf={selected === currentInstructorId} onBack={() => { setSelected(null); reload() }} />
+
+  return (
+    <>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      <div className={styles.card}>
+        <h2>Add instructor</h2>
+        <CreateInstructorForm onCreated={reload} />
+      </div>
+      <div className={styles.card}>
+        <h2>Instructors</h2>
+        {!instructors ? <p className={styles.muted}>Loading…</p> : (
+          <table>
+            <thead><tr><th>Name</th><th>Email</th><th>Role</th><th>Status</th><th>Last login</th><th /></tr></thead>
+            <tbody>
+              {instructors.map((i) => (
+                <tr key={i.instructor_id}>
+                  <td>{i.display_name}</td>
+                  <td>{i.email}</td>
+                  <td><span className={styles.pill}>{i.role}</span></td>
+                  <td><span className={`${styles.pill} ${i.status === 'active' ? styles.pillOk : styles.pillMuted}`}>{i.status}</span></td>
+                  <td>{i.last_login_at ? new Date(i.last_login_at).toLocaleString() : 'never'}</td>
+                  <td><button className={styles.linkBtn} onClick={() => setSelected(i.instructor_id)}>Open</button></td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+    </>
+  )
+}
+
+function CreateInstructorForm({ onCreated }) {
+  const [form, setForm] = useState({ email: '', display_name: '', role: 'instructor', password: '' })
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  const submit = async (e) => {
+    e.preventDefault()
+    setBusy(true); setError(null)
+    try {
+      await adminApi.createInstructor(form)
+      setForm({ email: '', display_name: '', role: 'instructor', password: '' })
+      onCreated()
+    } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  return (
+    <form onSubmit={submit}>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      <div className={styles.formRow}>
+        <div><label className={styles.label}>Name</label>
+          <input className={styles.input} value={form.display_name} onChange={(e) => setForm({ ...form, display_name: e.target.value })} required /></div>
+        <div><label className={styles.label}>Email</label>
+          <input className={styles.input} type="email" value={form.email} onChange={(e) => setForm({ ...form, email: e.target.value })} required /></div>
+        <div><label className={styles.label}>Role</label>
+          <select className={styles.select} value={form.role} onChange={(e) => setForm({ ...form, role: e.target.value })}>
+            <option value="instructor">instructor</option>
+            <option value="admin">admin</option>
+            <option value="owner">owner</option>
+          </select></div>
+        <div><label className={styles.label}>Temporary password (12+ chars)</label>
+          <input className={styles.input} type="password" value={form.password} onChange={(e) => setForm({ ...form, password: e.target.value })} required minLength={12} /></div>
+        <div><button className={styles.btn} disabled={busy}>{busy ? 'Adding…' : 'Add instructor'}</button></div>
+      </div>
+    </form>
+  )
+}
+
+function InstructorDetail({ instructorId, isSelf, onBack }) {
+  const [instructor, setInstructor] = useState(null)
+  const [error, setError] = useState(null)
+  const [notice, setNotice] = useState(null)
+  const [busy, setBusy] = useState(false)
+  const [newPassword, setNewPassword] = useState('')
+
+  const reload = useCallback(() => {
+    adminApi.instructor(instructorId).then(setInstructor).catch((e) => setError(e.message))
+  }, [instructorId])
+  useEffect(reload, [reload])
+
+  const updateRole = async (role) => {
+    setBusy(true); setError(null); setNotice(null)
+    try { await adminApi.updateInstructor(instructorId, { role }); reload() }
+    catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const toggleStatus = async () => {
+    const status = instructor.status === 'active' ? 'inactive' : 'active'
+    setBusy(true); setError(null); setNotice(null)
+    try { await adminApi.updateInstructor(instructorId, { status }); reload() }
+    catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const revokeSessions = async () => {
+    setBusy(true); setError(null)
+    try { await adminApi.revokeInstructorSessions(instructorId); setNotice('All sessions revoked.'); reload() }
+    catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const resetPassword = async (e) => {
+    e.preventDefault()
+    setBusy(true); setError(null); setNotice(null)
+    try { await adminApi.resetInstructorPassword(instructorId, newPassword); setNewPassword(''); setNotice('Password reset. All of their sessions were revoked.') }
+    catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  if (!instructor) return error ? <div className={styles.errorBox}>{error}</div> : <p className={styles.muted}>Loading…</p>
+
+  return (
+    <>
+      <button className={styles.linkBtn} onClick={onBack}>&larr; Back to instructors</button>
+      <h2 style={{ margin: '1rem 0' }}>{instructor.display_name} <span className={styles.muted}>({instructor.email})</span></h2>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      {notice && <p className={styles.muted}>{notice}</p>}
+
+      <div className={styles.card}>
+        <h3>Role &amp; status</h3>
+        <div className={styles.formRow}>
+          <div><label className={styles.label}>Role</label>
+            <select className={styles.select} value={instructor.role} onChange={(e) => updateRole(e.target.value)} disabled={busy}>
+              <option value="instructor">instructor</option>
+              <option value="admin">admin</option>
+              <option value="owner">owner</option>
+            </select></div>
+          <div><button className={instructor.status === 'active' ? styles.btnDanger : styles.btnSecondary} onClick={toggleStatus} disabled={busy}>
+            {instructor.status === 'active' ? 'Deactivate' : 'Activate'}
+          </button></div>
+        </div>
+        {isSelf && <p className={styles.muted}>This is your own account — the platform refuses to remove the last active owner, whichever account that is.</p>}
+      </div>
+
+      <div className={styles.card}>
+        <h3>Sessions</h3>
+        <p className={styles.muted}>Last login: {instructor.last_login_at ? new Date(instructor.last_login_at).toLocaleString() : 'never'}</p>
+        {instructor.sessions?.length ? (
+          <table>
+            <thead><tr><th>Created</th><th>Last active</th><th>Expires</th><th>Status</th></tr></thead>
+            <tbody>
+              {instructor.sessions.map((s) => (
+                <tr key={s.session_id}>
+                  <td>{new Date(s.created_at).toLocaleString()}</td>
+                  <td>{new Date(s.last_seen_at).toLocaleString()}</td>
+                  <td>{new Date(s.expires_at).toLocaleString()}</td>
+                  <td>{s.revoked_at ? <span className={`${styles.pill} ${styles.pillMuted}`}>revoked</span> : <span className={`${styles.pill} ${styles.pillOk}`}>active</span>}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        ) : <p className={styles.muted}>No sessions on record.</p>}
+        <button className={styles.btnDanger} style={{ marginTop: '0.75rem' }} onClick={revokeSessions} disabled={busy}>Revoke all sessions</button>
+      </div>
+
+      <div className={styles.card}>
+        <h3>Reset password</h3>
+        <form onSubmit={resetPassword} className={styles.formRow}>
+          <div><input className={styles.input} type="password" placeholder="New password (12+ chars)" value={newPassword} onChange={(e) => setNewPassword(e.target.value)} minLength={12} required /></div>
+          <div><button className={styles.btn} disabled={busy}>Set new password</button></div>
+        </form>
+      </div>
+    </>
+  )
+}

frontend/src/admin/LearningView.jsx

@@ -0,0 +1,160 @@
+import { useState, useEffect, useCallback } from 'react'
+import { adminApi } from './api'
+import styles from './Admin.module.css'
+
+// Instructor learning analytics — cohort summary, "needs attention," per-scenario analytics,
+// and a student drill-down. Deliberately no leaderboards or scoring language — this is
+// instructional visibility, not a ranking (docs/PHASE3B_LEARNING_AND_ASSESSMENT.md §13).
+export default function LearningView() {
+  const [cohorts, setCohorts] = useState(null)
+  const [cohortId, setCohortId] = useState(null)
+  const [summary, setSummary] = useState(null)
+  const [needsAttention, setNeedsAttention] = useState(null)
+  const [scenarioStats, setScenarioStats] = useState(null)
+  const [selectedStudent, setSelectedStudent] = useState(null)
+  const [error, setError] = useState(null)
+
+  useEffect(() => { adminApi.cohorts().then((c) => { setCohorts(c); if (c[0]) setCohortId(c[0].cohort_id) }).catch((e) => setError(e.message)) }, [])
+
+  const reload = useCallback(() => {
+    if (!cohortId) return
+    adminApi.cohortLearning(cohortId).then(setSummary).catch((e) => setError(e.message))
+    adminApi.needsAttention(cohortId).then(setNeedsAttention).catch((e) => setError(e.message))
+    adminApi.scenarioAnalytics(cohortId).then(setScenarioStats).catch((e) => setError(e.message))
+  }, [cohortId])
+  useEffect(reload, [reload])
+
+  if (selectedStudent) return <StudentLearningDetail studentId={selectedStudent} onBack={() => setSelectedStudent(null)} />
+
+  return (
+    <>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      <div className={styles.card}>
+        <label className={styles.label}>Cohort</label>
+        <select className={styles.select} value={cohortId || ''} onChange={(e) => setCohortId(e.target.value)}>
+          {cohorts?.map((c) => <option key={c.cohort_id} value={c.cohort_id}>{c.name}</option>)}
+        </select>
+      </div>
+
+      {summary && (
+        <div className={styles.card}>
+          <h2>Cohort Summary</h2>
+          <div className={styles.statGrid}>
+            <div className={styles.statCard}><div className={styles.statValue}>{summary.student_count}</div><div className={styles.statLabel}>Students</div></div>
+            <div className={styles.statCard}><div className={styles.statValue}>{summary.active_learners}</div><div className={styles.statLabel}>Active (7d)</div></div>
+            <div className={styles.statCard}><div className={styles.statValue}>{summary.overall_completion_pct}%</div><div className={styles.statLabel}>Avg. Completion</div></div>
+          </div>
+          <table>
+            <thead><tr><th>Stage</th><th>Students Complete</th></tr></thead>
+            <tbody>
+              {summary.stages.map((s) => (
+                <tr key={s.id}><td>{s.name}</td><td>{s.completedBy}/{summary.student_count} ({s.pct}%)</td></tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      )}
+
+      <div className={styles.card}>
+        <h2>Needs Attention</h2>
+        {!needsAttention ? <p className={styles.muted}>Loading…</p> : needsAttention.length === 0 ? <p className={styles.muted}>No signals right now.</p> : (
+          <table>
+            <thead><tr><th>Student</th><th>Signal</th><th>Detail</th><th /></tr></thead>
+            <tbody>
+              {needsAttention.map((s, i) => (
+                <tr key={i}>
+                  <td>{s.display_name}</td>
+                  <td><span className={`${styles.pill} ${styles.pillWarn}`}>{s.label}</span></td>
+                  <td className={styles.muted}>{s.detail}</td>
+                  <td><button className={styles.linkBtn} onClick={() => setSelectedStudent(s.student_id)}>View</button></td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+
+      <div className={styles.card}>
+        <h2>Scenario Analytics</h2>
+        {!scenarioStats ? <p className={styles.muted}>Loading…</p> : (
+          <table>
+            <thead><tr><th>Scenario</th><th>Completions</th><th>Avg Attempts</th><th>Failures</th><th>Hints Used</th><th>Avg Time</th></tr></thead>
+            <tbody>
+              {scenarioStats.map((s) => (
+                <tr key={s.scenario_id}>
+                  <td>{s.scenario_id}</td><td>{s.completions}</td><td>{s.avg_attempts}</td>
+                  <td>{s.total_failures}</td><td>{s.total_hints_used}</td>
+                  <td>{s.avg_duration_seconds ? `${Math.round(s.avg_duration_seconds / 60)}m` : '—'}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+    </>
+  )
+}
+
+function StudentLearningDetail({ studentId, onBack }) {
+  const [data, setData] = useState(null)
+  const [error, setError] = useState(null)
+
+  useEffect(() => { adminApi.studentLearning(studentId).then(setData).catch((e) => setError(e.message)) }, [studentId])
+
+  if (error) return <div className={styles.errorBox}>{error}</div>
+  if (!data) return <p className={styles.muted}>Loading…</p>
+
+  return (
+    <>
+      <button className={styles.linkBtn} onClick={onBack}>&larr; Back</button>
+      <h2 style={{ margin: '1rem 0' }}>{studentId}</h2>
+
+      {data.curriculum && (
+        <div className={styles.card}>
+          <h3>Curriculum ({data.curriculum.percent_complete}%)</h3>
+          {data.curriculum.stages.map((s) => (
+            <div key={s.id} style={{ fontSize: '0.85rem', padding: '0.2rem 0' }}>
+              {s.complete ? '✅' : s.locked ? '🔒' : '🟡'} {s.name} — {s.completed}/{s.total}
+            </div>
+          ))}
+        </div>
+      )}
+
+      <div className={styles.card}>
+        <h3>Attempts</h3>
+        <table>
+          <thead><tr><th>Scenario</th><th>Status</th><th>Validations</th><th>Hints (max level)</th><th>Duration</th></tr></thead>
+          <tbody>
+            {data.attempts.map((a, i) => (
+              <tr key={i}>
+                <td>{a.scenario_id}</td>
+                <td><span className={`${styles.pill} ${a.status === 'completed' ? styles.pillOk : styles.pillWarn}`}>{a.status}</span></td>
+                <td>{a.validation_pass_count} passed, {a.validation_fail_count} failed</td>
+                <td>{a.hint_count} ({a.highest_hint_level})</td>
+                <td>{a.duration_seconds ? `${Math.round(a.duration_seconds / 60)}m` : '—'}</td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      </div>
+
+      <div className={styles.card}>
+        <h3>Assessment History</h3>
+        {data.assessment_sessions.length === 0 ? <p className={styles.muted}>None yet.</p> : (
+          <table>
+            <thead><tr><th>Assessment</th><th>Status</th><th>Result</th></tr></thead>
+            <tbody>
+              {data.assessment_sessions.map((s) => (
+                <tr key={s.assessment_session_id}>
+                  <td>{s.title}</td>
+                  <td><span className={`${styles.pill} ${s.status === 'completed' ? styles.pillOk : styles.pillMuted}`}>{s.status}</span></td>
+                  <td>{s.result ? `${s.result.scenarios_passed}/${s.result.scenarios_total}` : '—'}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+    </>
+  )
+}

frontend/src/admin/StudentsView.jsx

@@ -0,0 +1,136 @@
+import { useState, useEffect, useCallback } from 'react'
+import { adminApi } from './api'
+import { StatusPill } from './CohortsView'
+import styles from './Admin.module.css'
+
+export default function StudentsView() {
+  const [students, setStudents] = useState(null)
+  const [selected, setSelected] = useState(null)
+  const [error, setError] = useState(null)
+
+  const reload = useCallback(() => {
+    adminApi.students().then(setStudents).catch((e) => setError(e.message))
+  }, [])
+  useEffect(reload, [reload])
+
+  if (selected) return <StudentDetail studentId={selected} onBack={() => { setSelected(null); reload() }} />
+
+  return (
+    <div className={styles.card}>
+      <h2>Students ({students?.length ?? '…'})</h2>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      {students && (
+        <table>
+          <thead><tr><th>Name</th><th>ID</th><th>Status</th><th>Last active</th><th /></tr></thead>
+          <tbody>
+            {students.map((s) => (
+              <tr key={s.student_id}>
+                <td>{s.display_name}</td>
+                <td className={styles.muted}>{s.student_id}</td>
+                <td><span className={`${styles.pill} ${s.status === 'active' ? styles.pillOk : styles.pillMuted}`}>{s.status}</span></td>
+                <td>{s.last_active_at ? new Date(s.last_active_at).toLocaleString() : 'never'}</td>
+                <td><button className={styles.linkBtn} onClick={() => setSelected(s.student_id)}>Open</button></td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      )}
+    </div>
+  )
+}
+
+function StudentDetail({ studentId, onBack }) {
+  const [progress, setProgress] = useState(null)
+  const [attempts, setAttempts] = useState(null)
+  const [env, setEnv] = useState(null)
+  const [events, setEvents] = useState(null)
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  const reload = useCallback(() => {
+    adminApi.studentProgress(studentId).then(setProgress).catch(() => {})
+    // Phase 4.1 §16 — studentAttempts is now paginated; this panel only ever shows the most
+    // recent page (labeled "Recent attempts," not a full history browser — see
+    // /api/admin/students/:id/attempts's own pagination for the underlying capability).
+    adminApi.studentAttempts(studentId).then((r) => setAttempts(r.items)).catch(() => {})
+    adminApi.studentEnvironment(studentId).then((rows) => setEnv(rows?.find((e) => e.status !== 'destroyed') || null)).catch(() => {})
+  }, [studentId])
+  useEffect(reload, [reload])
+
+  const withBusy = (fn) => async () => {
+    setBusy(true); setError(null)
+    try { await fn(); reload() } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const loadEvents = async () => {
+    if (!env) return
+    try { setEvents(await adminApi.environmentEvents(env.environment_id)) } catch (e) { setError(e.message) }
+  }
+
+  return (
+    <>
+      <button className={styles.linkBtn} onClick={onBack}>&larr; Back to students</button>
+      <h2 style={{ margin: '1rem 0' }}>{studentId}</h2>
+      {error && <div className={styles.errorBox}>{error}</div>}
+
+      <div className={styles.card}>
+        <h3>Environment</h3>
+        {!env ? <p className={styles.muted}>No Lab provisioned.</p> : (
+          <>
+            <p>Status: <StatusPill status={env.status} /> — Lab host: {env.lab_host_id} — created {new Date(env.created_at).toLocaleString()}</p>
+            {env.last_active_at && <p className={styles.muted}>Last active: {new Date(env.last_active_at).toLocaleString()}</p>}
+          </>
+        )}
+        <div className={styles.formRow} style={{ marginTop: '0.75rem' }}>
+          {!env && <button className={styles.btn} disabled={busy} onClick={withBusy(() => adminApi.provisionStudentLab(studentId))}>Provision Lab</button>}
+          {env && <button className={styles.btnSecondary} disabled={busy} onClick={withBusy(() => adminApi.resetEnvironment(env.environment_id))}>Reset/Recreate</button>}
+          {env && (
+            <button className={styles.btnDanger} disabled={busy} onClick={withBusy(async () => {
+              if (window.confirm('Destroy this Lab? Progress is not affected.')) await adminApi.destroyEnvironment(env.environment_id)
+            })}>Destroy Lab</button>
+          )}
+          {env && <button className={styles.linkBtn} onClick={loadEvents}>View event history</button>}
+        </div>
+        {events && (
+          <table style={{ marginTop: '0.75rem' }}>
+            <thead><tr><th>Event</th><th>Actor</th><th>When</th></tr></thead>
+            <tbody>
+              {events.map((e) => <tr key={e.id}><td>{e.event_type}</td><td>{e.actor}</td><td>{new Date(e.created_at).toLocaleString()}</td></tr>)}
+            </tbody>
+          </table>
+        )}
+      </div>
+
+      <div className={styles.card}>
+        <h3>Curriculum progress</h3>
+        {!progress ? <p className={styles.muted}>Loading…</p> : progress.stages.map((s) => (
+          <div key={s.id} style={{ marginBottom: '0.5rem' }}>
+            <strong>{s.name}</strong>
+            <div className={styles.muted}>
+              {s.scenarios.filter((sc) => sc.status === 'completed').length}/{s.scenarios.length} complete
+            </div>
+          </div>
+        ))}
+      </div>
+
+      <div className={styles.card}>
+        <h3>Recent attempts</h3>
+        {!attempts ? <p className={styles.muted}>Loading…</p> : attempts.length === 0 ? <p className={styles.muted}>None yet.</p> : (
+          <table>
+            <thead><tr><th>Scenario</th><th>Result</th><th>Checks</th><th>When</th></tr></thead>
+            <tbody>
+              {attempts.map((a) => (
+                <tr key={a.attempt_id}>
+                  <td>{a.scenario_id}</td>
+                  <td><span className={`${styles.pill} ${a.result === 'passed' ? styles.pillOk : styles.pillWarn}`}>{a.result}</span></td>
+                  <td className={styles.muted}>{a.validation_count ?? '—'}</td>
+                  <td>{new Date(a.created_at).toLocaleString()}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </div>
+    </>
+  )
+}

frontend/src/admin/api.js

@@ -0,0 +1,98 @@
+// Admin API client. Uses the rn_instructor session cookie exclusively (same-origin, sent
+// automatically) — completely separate credential/cookie from student sessions (see
+// platform/api/src/sessions.js). No admin data is ever cached client-side beyond the current
+// React state; nothing here reads or writes localStorage.
+//
+// rn_csrf_i is a deliberately non-HttpOnly cookie (double-submit CSRF pattern, mirrored on the
+// student side in frontend/src/platform/api.js) — read here and echoed back as a header on
+// every state-changing request.
+
+const CSRF_COOKIE = 'rn_csrf_i'
+
+function getCookie(name) {
+  return document.cookie.split('; ').find((c) => c.startsWith(`${name}=`))?.split('=')[1]
+}
+
+async function json(res) {
+  if (!res.ok) {
+    const body = await res.json().catch(() => ({}))
+    throw new Error(body.message || body.error || `Request failed (${res.status})`)
+  }
+  return res.json()
+}
+
+function withCsrf(init) {
+  return { ...init, headers: { ...init.headers, 'X-CSRF-Token': getCookie(CSRF_COOKIE) || '' } }
+}
+function post(path, body) {
+  return fetch(path, withCsrf({ method: 'POST', headers: { 'Content-Type': 'application/json' }, body: body ? JSON.stringify(body) : undefined })).then(json)
+}
+function patch(path, body) {
+  return fetch(path, withCsrf({ method: 'PATCH', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) })).then(json)
+}
+function del(path) {
+  return fetch(path, withCsrf({ method: 'DELETE' })).then(json)
+}
+function get(path) {
+  return fetch(path).then(json)
+}
+
+export const adminApi = {
+  // No CSRF token yet at login (nothing authenticated to forge into).
+  login: (email, password) => fetch('/api/auth/instructor/login', {
+    method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ email, password }),
+  }).then(json),
+  logout: () => post('/api/auth/logout'),
+  session: () => get('/api/auth/session'),
+  changePassword: (old_password, new_password) => post('/api/auth/change-password', { old_password, new_password }),
+
+  dashboard: () => get('/api/admin/dashboard'),
+
+  students: () => get('/api/admin/students'),
+  createStudent: (display_name, cohort_id) => post('/api/admin/students', { display_name, cohort_id }),
+  updateStudent: (id, fields) => patch(`/api/admin/students/${id}`, fields),
+  studentProgress: (id) => get(`/api/admin/students/${id}/progress`),
+  studentAttempts: (id, page = 1) => get(`/api/admin/students/${id}/attempts?page=${page}`), // Phase 4.1 §16 — paginated, see pagination.js
+  studentEnvironment: (id) => get(`/api/admin/students/${id}/environment`),
+  provisionStudentLab: (id) => post(`/api/admin/students/${id}/environment/provision`),
+  assignStudentCohort: (id, cohort_id) => post(`/api/admin/students/${id}/cohort`, { cohort_id }),
+  removeStudentCohort: (id, cohortId) => del(`/api/admin/students/${id}/cohort/${cohortId}`),
+
+  cohorts: () => get('/api/admin/cohorts'),
+  createCohort: (fields) => post('/api/admin/cohorts', fields),
+  updateCohort: (id, fields) => patch(`/api/admin/cohorts/${id}`, fields),
+  cohortStudents: (id) => get(`/api/admin/cohorts/${id}/students`),
+  cohortProgress: (id) => get(`/api/admin/cohorts/${id}/progress`),
+  assignCohortCurriculum: (id, curriculum_path) => post(`/api/admin/cohorts/${id}/curriculum`, { curriculum_path }),
+  assignCohortInstructor: (id, instructor_id, role_in_cohort) => post(`/api/admin/cohorts/${id}/instructors`, { instructor_id, role_in_cohort }),
+  prepareLabs: (id) => post(`/api/admin/cohorts/${id}/prepare-labs`),
+  destroyLabs: (id) => post(`/api/admin/cohorts/${id}/destroy-labs`),
+
+  resetEnvironment: (id) => post(`/api/admin/environments/${id}/reset`),
+  destroyEnvironment: (id) => del(`/api/admin/environments/${id}`),
+  environmentEvents: (id) => get(`/api/admin/environments/${id}/events`),
+
+  instructors: () => get('/api/admin/instructors'),
+  createInstructor: (fields) => post('/api/admin/instructors', fields),
+  instructor: (id) => get(`/api/admin/instructors/${id}`),
+  updateInstructor: (id, fields) => patch(`/api/admin/instructors/${id}`, fields),
+  revokeInstructorSessions: (id) => post(`/api/admin/instructors/${id}/revoke-sessions`),
+  resetInstructorPassword: (id, new_password) => post(`/api/admin/instructors/${id}/reset-password`, { new_password }),
+
+  auditEvents: (page = 1) => get(`/api/admin/audit-events?page=${page}`), // Phase 4.1 §16 — paginated, see pagination.js
+
+  // ── Phase 3B: learning analytics ────────────────────────────────────────────────────────
+  cohortLearning: (id) => get(`/api/admin/cohorts/${id}/learning`),
+  studentLearning: (id) => get(`/api/admin/students/${id}/learning`),
+  scenarioAnalytics: (cohortId) => get(`/api/admin/scenario-analytics${cohortId ? `?cohort_id=${cohortId}` : ''}`),
+  needsAttention: (cohortId) => get(`/api/admin/cohorts/${cohortId}/needs-attention`),
+  scenarioCatalog: () => get('/api/admin/scenario-catalog'), // Phase 4.1 §18 — structured assessment editor
+
+  // ── Phase 3B: assessment (exam + capstone) management ───────────────────────────────────
+  assessments: () => get('/api/admin/assessments'),
+  createAssessment: (fields) => post('/api/admin/assessments', fields),
+  updateAssessment: (id, fields) => patch(`/api/admin/assessments/${id}`, fields),
+  assignAssessment: (id, cohort_id) => post(`/api/admin/assessments/${id}/assign`, { cohort_id }),
+  assessmentSessions: (id, page = 1) => get(`/api/admin/assessments/${id}/sessions?page=${page}`), // Phase 4.1 §16 — paginated, see pagination.js
+  cancelAssessmentSession: (sessionId) => post(`/api/admin/assessment-sessions/${sessionId}/cancel`),
+}

frontend/src/components/AssessmentBanner.jsx

@@ -0,0 +1,47 @@
+import { useState, useEffect } from 'react'
+
+// Phase 3B — shows when the student has an active Platform-level assessment (exam or capstone)
+// running, distinct from the pre-existing Lab-local exam mode (ExamTimer/ExamSession above,
+// which predates this and stays untouched). Polls /api/assessments/active, which 404s/errors
+// harmlessly in standalone/single-container dev mode (no Platform API there at all) — so this
+// component renders nothing in that mode, by design.
+export default function AssessmentBanner() {
+  const [active, setActive] = useState(null)
+  const [remaining, setRemaining] = useState(null)
+
+  useEffect(() => {
+    let cancelled = false
+    function poll() {
+      fetch('/api/assessments/active').then((r) => r.json()).then((d) => {
+        if (!cancelled) setActive(d.active ? d : null)
+      }).catch(() => { if (!cancelled) setActive(null) })
+    }
+    poll()
+    const id = setInterval(poll, 15000)
+    return () => { cancelled = true; clearInterval(id) }
+  }, [])
+
+  useEffect(() => {
+    if (!active) return
+    const tick = () => setRemaining(Math.max(0, new Date(active.expires_at) - Date.now()))
+    tick()
+    const id = setInterval(tick, 1000)
+    return () => clearInterval(id)
+  }, [active])
+
+  if (!active) return null
+  const m = Math.floor(remaining / 60000), s = Math.floor((remaining % 60000) / 1000)
+  const completedCount = active.scenarios.filter((sc) => sc.status === 'completed').length
+
+  return (
+    <div style={{
+      display: 'flex', alignItems: 'center', gap: '1rem', padding: '0.5rem 1rem',
+      background: 'var(--amber-dim)', color: 'var(--amber)', fontSize: '0.85rem', fontFamily: 'var(--mono)',
+      borderBottom: '1px solid var(--border)',
+    }}>
+      <span>🎯 Assessment Mode: {active.title}</span>
+      <span>{completedCount}/{active.scenarios.length} scenarios complete</span>
+      <span>⏱ {m}m {s}s remaining</span>
+    </div>
+  )
+}

frontend/src/components/ProgressiveHints.jsx

@@ -0,0 +1,91 @@
+import { useState, useEffect, useCallback } from 'react'
+import ReactMarkdown from 'react-markdown'
+import remarkGfm from 'remark-gfm'
+import styles from './ScenarioPanel.module.css'
+
+// Phase 3B progressive hints — used when the Gateway has stripped the full `hints` array from
+// the scenario payload (the multi-student, Platform-mediated deployment; see
+// platform/gateway/src/server.js's GET /lab/:token/api/scenarios/:scenarioId). Hints are
+// fetched one at a time from the Platform API, server-enforced sequential (can't skip to hint
+// 3), and every reveal is recorded against the student's attempt — none of that is possible
+// with the old fully-preloaded array this replaces for this deployment mode.
+//
+// In standalone/single-container dev mode there's no Gateway rewrite, so `scenario.hints` is
+// still the full array and ScenarioPanel never renders this component at all — see the
+// `hintCount != null` check at the call site.
+export default function ProgressiveHints({ scenarioId, totalHints }) {
+  const [revealed, setRevealed] = useState([]) // [{level, title, body, command}]
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState(null)
+  const [copiedIdx, setCopiedIdx] = useState(null)
+  const [assessmentHintPolicy, setAssessmentHintPolicy] = useState(null) // null = not in an assessment; 'free'|'disabled'|'flagged'
+
+  // A scenario/environment change resets local reveal state — the server is still the source
+  // of truth (GET /attempt would show the real highest_hint_level), this is just what's
+  // rendered locally this session. Also checks whether this scenario is part of an active
+  // Platform assessment, purely to show the policy indicator pre-emptively (the server enforces
+  // the policy regardless, on every reveal call — this is UX, not the security boundary).
+  useEffect(() => {
+    setRevealed([]); setError(null); setAssessmentHintPolicy(null)
+    fetch('/api/assessments/active').then((r) => r.json()).then((d) => {
+      if (d.active && d.scenarios?.some((s) => s.scenario_id === scenarioId)) setAssessmentHintPolicy(d.hint_policy)
+    }).catch(() => {})
+  }, [scenarioId])
+
+  const revealNext = useCallback(async () => {
+    setLoading(true); setError(null)
+    try {
+      const r = await fetch(`api/scenarios/${scenarioId}/hint`, { method: 'POST' })
+      const d = await r.json()
+      if (!r.ok) { setError(d.message || d.error || 'Could not reveal a hint.'); return }
+      setRevealed((h) => [...h, { level: d.level, ...d.hint }])
+    } catch {
+      setError('Could not reach the platform to reveal a hint.')
+    } finally {
+      setLoading(false)
+    }
+  }, [scenarioId])
+
+  function copyCmd(cmd, idx) {
+    if (navigator.clipboard && window.isSecureContext) {
+      navigator.clipboard.writeText(cmd).then(() => { setCopiedIdx(idx); setTimeout(() => setCopiedIdx(null), 1800) })
+    }
+  }
+
+  if (totalHints === 0) return <div className={styles.noHints}>No hints available for this scenario.</div>
+
+  if (assessmentHintPolicy === 'disabled' && revealed.length === 0) {
+    return <div className={styles.noHints}>Hints Disabled — this assessment does not allow hints.</div>
+  }
+
+  return (
+    <div>
+      {assessmentHintPolicy === 'flagged' && <div className={styles.setupNote} style={{ marginBottom: '0.75rem' }}>Using a hint will be recorded.</div>}
+      {revealed.map((hint, i) => (
+        <div key={i} className={styles.hintCard}>
+          <div className={styles.hintHeader}>
+            <div className={styles.hintLeft}>
+              <span className={styles.hintNum}>Hint {hint.level}</span>
+              <span className={styles.hintTitle}>{hint.title}</span>
+            </div>
+          </div>
+          <div className={styles.hintBody}>
+            <p className={styles.hintText}><ReactMarkdown remarkPlugins={[remarkGfm]}>{hint.body}</ReactMarkdown></p>
+            {hint.command && (
+              <div className={styles.cmdBlock}>
+                <pre className={styles.cmdPre}>{hint.command}</pre>
+                <button className={styles.copyBtn} onClick={() => copyCmd(hint.command, i)}>{copiedIdx === i ? '✓ Copied' : 'Copy'}</button>
+              </div>
+            )}
+          </div>
+        </div>
+      ))}
+      {error && <div className={styles.validateError}>⚠ {error}</div>}
+      {revealed.length < totalHints && (
+        <button className={styles.setupBtn} disabled={loading} onClick={revealNext}>
+          {loading ? 'Revealing…' : `Reveal Hint ${revealed.length + 1} of ${totalHints}`}
+        </button>
+      )}
+    </div>
+  )
+}

frontend/src/components/ScenarioPanel.jsx

@@ -3,6 +3,7 @@ import ReactMarkdown from 'react-markdown'
 import remarkGfm from 'remark-gfm'
 import styles from './ScenarioPanel.module.css'
 import { useConfirm } from './useConfirm'
+import ProgressiveHints from './ProgressiveHints'
 
 // Inline markdown: renders without a wrapping <p> — safe for buttons/spans
 const inlineComponents = {
@@ -48,6 +49,15 @@ export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioSt
     setHintsRevealed([])
   }, [scenario?.id])
 
+  // Phase 3B attempt telemetry — fire-and-forget "scenario started" so the Platform can record
+  // a real started_at for this working session. Only meaningful under the Platform-multiplied
+  // deployment (routed through the Gateway); 404s harmlessly in standalone/single-container dev
+  // mode, where there's no Platform API to reach at all.
+  useEffect(() => {
+    if (!scenario?.id) return
+    fetch(`api/scenarios/${scenario.id}/start`, { method: 'POST' }).catch(() => {})
+  }, [scenario?.id])
+
   const timeSpentRef = useRef(0)
   const lastScenarioIdRef = useRef(null)
 
@@ -341,7 +351,7 @@ export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioSt
             onClick={() => setTab(t)}
           >
             {t === 'problem' ? '📄 Problem'
-              : t === 'hints' ? `💡 Hints (${scenario.hints?.length || 0})`
+              : t === 'hints' ? `💡 Hints (${scenario.hints?.length ?? scenario.hint_count ?? 0})`
               : '✓ Validate'}
           </button>
         ))}
@@ -448,6 +458,15 @@ export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioSt
         {/* HINTS TAB */}
         {tab === 'hints' && (
           <div className={styles.tabPane} style={{ animation: 'fadeIn 0.2s ease' }}>
+            {/* Phase 3B: the Gateway strips `hints` from the payload under the Platform-
+                multiplied deployment (see platform/gateway/src/server.js) — hint_count survives
+                as the signal to switch to server-gated progressive reveal instead of the old
+                fully-preloaded array. Standalone/dev mode still has the full array (no Gateway
+                rewrite happens there) and keeps the original behavior untouched below. */}
+            {scenario.hints === undefined && typeof scenario.hint_count === 'number' ? (
+              <ProgressiveHints scenarioId={scenario.id} totalHints={scenario.hint_count} />
+            ) : (
+              <>
             {scenario.hints?.length === 0 && (
               <div className={styles.noHints}>No hints available for this scenario.</div>
             )}
@@ -483,6 +502,8 @@ export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioSt
                 </div>
               )
             })}
+              </>
+            )}
           </div>
         )}
 

frontend/src/main.jsx

@@ -1,14 +1,25 @@
 import React from 'react'
 import ReactDOM from 'react-dom/client'
 import App from './App.jsx'
+import PlatformShell from './platform/PlatformShell.jsx'
+import AdminPortal from './admin/AdminPortal.jsx'
 import './index.css'
 
 // Apply saved theme before first paint to avoid flash
 const savedTheme = localStorage.getItem('kubekosh-theme') || 'dark'
 document.documentElement.setAttribute('data-theme', savedTheme)
 
+// This bundle is served both by the lightweight Platform API (root paths + /admin) and by
+// every ephemeral per-student Lab container (reached via the Gateway at /lab/<token>/) — same
+// build, same code, split purely by the URL path at runtime. See
+// docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md "Student/admin flow" for why: it lets the existing
+// Lab UI (<App/>) stay completely unmodified while the Platform Shell and Admin Portal live
+// alongside it in the same bundle.
+const path = window.location.pathname
+const view = path.startsWith('/lab/') ? 'lab' : path.startsWith('/admin') ? 'admin' : 'platform'
+
 ReactDOM.createRoot(document.getElementById('root')).render(
   <React.StrictMode>
-    <App />
+    {view === 'lab' ? <App /> : view === 'admin' ? <AdminPortal /> : <PlatformShell />}
   </React.StrictMode>
 )

frontend/src/platform/AchievementsTab.jsx

@@ -0,0 +1,40 @@
+import { useState, useEffect } from 'react'
+import { api } from './api'
+import styles from './Platform.module.css'
+
+const LABELS = {
+  stage_completed: 'Stage completed', curriculum_completed: 'Curriculum completed',
+  assessment_completed: 'Assessment completed', capstone_completed: 'Capstone completed',
+}
+const ICONS = {
+  stage_completed: '✅', curriculum_completed: '🎓', assessment_completed: '📝', capstone_completed: '🏁',
+}
+
+// Not a public certificate — a durable internal record. Phase 4/5 can render a certificate from
+// these later (docs/PHASE3B_LEARNING_AND_ASSESSMENT.md §16); nothing here is shareable yet.
+export default function AchievementsTab() {
+  const [achievements, setAchievements] = useState(null)
+  const [error, setError] = useState(null)
+
+  useEffect(() => {
+    api.achievements().then(setAchievements).catch((e) => setError(e.message))
+  }, [])
+
+  return (
+    <section className={styles.card}>
+      <h2>Achievements &amp; History</h2>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      {!achievements ? <p className={styles.muted}>Loading…</p> : achievements.length === 0 ? <p className={styles.muted}>Nothing yet — complete a stage to see it here.</p> : (
+        achievements.map((a) => (
+          <div key={a.achievement_id} style={{ display: 'flex', alignItems: 'center', gap: '0.6rem', padding: '0.5rem 0', borderBottom: '1px solid var(--border)' }}>
+            <span style={{ fontSize: '1.2rem' }}>{ICONS[a.achievement_type] || '🏅'}</span>
+            <div>
+              <div>{LABELS[a.achievement_type] || a.achievement_type}{a.stage_id ? `: ${a.stage_id}` : ''}{a.metadata?.title ? `: ${a.metadata.title}` : ''}</div>
+              <div className={styles.muted} style={{ fontSize: '0.78rem' }}>{new Date(a.achieved_at).toLocaleString()}</div>
+            </div>
+          </div>
+        ))
+      )}
+    </section>
+  )
+}

frontend/src/platform/AssessmentsTab.jsx

@@ -0,0 +1,113 @@
+import { useState, useEffect, useCallback } from 'react'
+import { api } from './api'
+import styles from './Platform.module.css'
+
+// Available exams (assigned to the student's cohort), an active session if one is running (with
+// a live countdown), and completed history. Starting an exam draws its scenario set
+// server-side — the student works through it inside their existing Lab, the same one My
+// Learning launches (see docs/PHASE3B_LEARNING_AND_ASSESSMENT.md §9 for why a separate Lab
+// per assessment isn't needed).
+export default function AssessmentsTab() {
+  const [assessments, setAssessments] = useState(null)
+  const [active, setActive] = useState(null)
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  const reload = useCallback(() => {
+    api.assessments().then(setAssessments).catch((e) => setError(e.message))
+    api.activeAssessment().then(setActive).catch(() => {})
+  }, [])
+  useEffect(reload, [reload])
+
+  const handleStart = async (definitionId) => {
+    setBusy(true); setError(null)
+    try { await api.startAssessment(definitionId); reload() }
+    catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  return (
+    <>
+      {error && <div className={styles.errorBox}>{error}</div>}
+
+      {active?.active && (
+        <section className={styles.card}>
+          <h2>Active Assessment</h2>
+          <p><strong>{active.title}</strong></p>
+          <CountdownLine expiresAt={active.expires_at} />
+          <table className={styles.dataTable} style={{ marginTop: '0.75rem' }}>
+            <thead><tr><th>#</th><th>Scenario</th><th>Status</th></tr></thead>
+            <tbody>
+              {active.scenarios.map((s) => (
+                <tr key={s.scenario_id}>
+                  <td>{s.position + 1}</td><td>{s.scenario_id}</td>
+                  <td>
+                    {s.status === 'completed' ? <span className={`${styles.pill} ${styles.pillOk}`}>completed</span>
+                      : <span className={`${styles.pill} ${styles.pillMuted}`}>{s.status}</span>}
+                  </td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+          <p className={styles.hint} style={{ marginTop: '0.75rem' }}>Launch your Lab from My Learning and work through these scenarios there — this list stays in sync automatically.</p>
+        </section>
+      )}
+
+      <section className={styles.card}>
+        <h2>Available Assessments</h2>
+        {!assessments ? <p className={styles.muted}>Loading…</p> : assessments.length === 0 ? <p className={styles.muted}>None assigned to your cohort yet.</p> : (
+          assessments.map((a) => {
+            const completedSessions = a.sessions.filter((s) => s.status === 'completed')
+            return (
+              <div key={a.assessment_definition_id} style={{ padding: '0.75rem 0', borderBottom: '1px solid var(--border)' }}>
+                <p><strong>{a.title}</strong> <span className={styles.muted}>· {a.duration_minutes} min</span></p>
+                {a.description && <p className={styles.muted} style={{ fontSize: '0.85rem' }}>{a.description}</p>}
+                {completedSessions.length > 0 && (
+                  <p className={styles.hint}>Completed {completedSessions.length}× — best result: {completedSessions.some((s) => s.result?.passed) ? 'passed' : 'not yet passed'}</p>
+                )}
+                {!active?.active && (
+                  <button className={styles.secondaryBtn} disabled={busy} onClick={() => handleStart(a.assessment_definition_id)}>
+                    {busy ? 'Starting…' : 'Start'}
+                  </button>
+                )}
+              </div>
+            )
+          })
+        )}
+      </section>
+
+      <section className={styles.card}>
+        <h2>History</h2>
+        {!assessments ? <p className={styles.muted}>Loading…</p> : (
+          <table className={styles.dataTable}>
+            <thead><tr><th>Assessment</th><th>Started</th><th>Status</th><th>Result</th></tr></thead>
+            <tbody>
+              {assessments.flatMap((a) => a.sessions).filter((s) => s.status !== 'not_started').sort((a, b) => new Date(b.started_at) - new Date(a.started_at)).map((s) => (
+                <tr key={s.assessment_session_id}>
+                  <td>{assessments.find((a) => a.sessions.includes(s))?.title}</td>
+                  <td>{s.started_at ? new Date(s.started_at).toLocaleString() : '—'}</td>
+                  <td><StatusPill status={s.status} /></td>
+                  <td>{s.result ? `${s.result.scenarios_passed}/${s.result.scenarios_total}` : '—'}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </section>
+    </>
+  )
+}
+
+function StatusPill({ status }) {
+  const cls = status === 'completed' ? styles.pillOk : status === 'expired' || status === 'cancelled' ? styles.pillErr : styles.pillWarn
+  return <span className={`${styles.pill} ${cls}`}>{status}</span>
+}
+
+function CountdownLine({ expiresAt }) {
+  const [remaining, setRemaining] = useState(() => Math.max(0, new Date(expiresAt) - Date.now()))
+  useEffect(() => {
+    const id = setInterval(() => setRemaining(Math.max(0, new Date(expiresAt) - Date.now())), 1000)
+    return () => clearInterval(id)
+  }, [expiresAt])
+  const m = Math.floor(remaining / 60000), s = Math.floor((remaining % 60000) / 1000)
+  return <p className={styles.statusLine}><span className={styles.spinner} /> Time remaining: {m}m {s}s</p>
+}

frontend/src/platform/CapstoneTab.jsx

@@ -0,0 +1,89 @@
+import { useState, useEffect, useCallback } from 'react'
+import { api } from './api'
+import styles from './Platform.module.css'
+
+const STAGE_NAMES = {
+  foundation: 'Foundation', workloads: 'Workloads', networking: 'Networking',
+  configuration: 'Configuration', troubleshooting: 'Troubleshooting', 'real-ops': 'RootNode: Real Ops',
+}
+
+export default function CapstoneTab() {
+  const [capstone, setCapstone] = useState(null)
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+
+  const reload = useCallback(() => {
+    api.capstone().then(setCapstone).catch((e) => setError(e.message))
+  }, [])
+  useEffect(reload, [reload])
+
+  const handleStart = async () => {
+    setBusy(true); setError(null)
+    try { await api.startAssessment(capstone.assessment_definition_id); reload() }
+    catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  if (error) return <div className={styles.errorBox}>{error}</div>
+  if (!capstone) return <p className={styles.muted}>Loading…</p>
+
+  if (capstone.status === 'locked') {
+    return (
+      <section className={styles.card}>
+        <h2>Capstone</h2>
+        <div className={styles.lockedBox}>
+          <p style={{ fontSize: '2rem' }}>🔒</p>
+          <p>Complete the rest of the curriculum to unlock the RootNode Capstone.</p>
+        </div>
+        <h3 style={{ marginTop: '1rem', fontSize: '0.9rem' }}>Prerequisites</h3>
+        {capstone.blocking_stage_ids.map((id) => (
+          <div key={id} className={styles.checklistItem}><span>⬜</span> {STAGE_NAMES[id] || id}</div>
+        ))}
+      </section>
+    )
+  }
+
+  const activeSession = capstone.sessions.find((s) => s.status === 'in_progress');
+  const completedSession = capstone.sessions.find((s) => s.status === 'completed' && s.result?.passed);
+
+  return (
+    <section className={styles.card}>
+      <h2>Capstone {capstone.status === 'completed' ? <span className={`${styles.pill} ${styles.pillOk}`} style={{ marginLeft: '0.5rem' }}>completed</span> : <span className={`${styles.pill} ${styles.pillOk}`} style={{ marginLeft: '0.5rem' }}>unlocked</span>}</h2>
+      {capstone.definition && (
+        <>
+          <p><strong>{capstone.definition.title}</strong> <span className={styles.muted}>· {capstone.definition.duration_minutes} min</span></p>
+          <p className={styles.muted} style={{ fontSize: '0.85rem' }}>{capstone.definition.description}</p>
+        </>
+      )}
+
+      {completedSession ? (
+        <p className={styles.hint} style={{ marginTop: '1rem' }}>
+          Completed {new Date(completedSession.submitted_at).toLocaleString()} — {completedSession.result.scenarios_passed}/{completedSession.result.scenarios_total} scenarios passed.
+        </p>
+      ) : activeSession ? (
+        <p className={styles.hint} style={{ marginTop: '1rem' }}>Your Capstone is in progress — launch your Lab from My Learning to continue.</p>
+      ) : (
+        <button className={styles.primaryBtn} style={{ marginTop: '1rem' }} disabled={busy} onClick={handleStart}>
+          {busy ? 'Starting…' : 'Start Capstone'}
+        </button>
+      )}
+
+      {capstone.sessions.length > 0 && (
+        <>
+          <h3 style={{ marginTop: '1.5rem', fontSize: '0.9rem' }}>Attempt History</h3>
+          <table className={styles.dataTable}>
+            <thead><tr><th>Started</th><th>Status</th><th>Result</th></tr></thead>
+            <tbody>
+              {capstone.sessions.map((s) => (
+                <tr key={s.assessment_session_id}>
+                  <td>{s.started_at ? new Date(s.started_at).toLocaleString() : '—'}</td>
+                  <td>{s.status}</td>
+                  <td>{s.result ? `${s.result.scenarios_passed}/${s.result.scenarios_total}` : '—'}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </>
+      )}
+    </section>
+  )
+}

frontend/src/platform/EntryScreen.jsx

@@ -0,0 +1,72 @@
+import { useState, useEffect } from 'react'
+import { api } from './api'
+import styles from './Platform.module.css'
+
+// A. Entry screen — RootNode Academy branding, choose your name from roster, no password.
+// Explicitly pilot/dev identity, not production auth — see
+// docs/PHASE2A_GATEWAY_AND_STUDENT_FLOW.md "Student identity limitation."
+export default function EntryScreen({ onLogin }) {
+  const [cohorts, setCohorts] = useState([])
+  const [cohort, setCohort] = useState('')
+  const [roster, setRoster] = useState([])
+  const [studentId, setStudentId] = useState('')
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState(null)
+
+  useEffect(() => {
+    api.cohorts().then(setCohorts).catch((e) => setError(e.message))
+  }, [])
+
+  useEffect(() => {
+    if (!cohort) { setRoster([]); return }
+    api.roster(cohort).then(setRoster).catch((e) => setError(e.message))
+  }, [cohort])
+
+  const handleLogin = async () => {
+    if (!studentId) return
+    setLoading(true)
+    setError(null)
+    try {
+      const student = await api.login(studentId)
+      onLogin(student)
+    } catch (e) {
+      setError(e.message)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  return (
+    <div className={styles.entryWrap}>
+      <div className={styles.entryCard}>
+        <div className={styles.brand}>
+          <span className={styles.brandIcon}>⎈</span> RootNode Academy
+        </div>
+        <p className={styles.tagline}>Real-world Kubernetes labs. Pick your name to continue.</p>
+        <p className={styles.pilotNote}>Pilot identity — no password. Not production auth.</p>
+
+        {error && <div className={styles.errorBox}>{error}</div>}
+
+        <label className={styles.label}>Cohort</label>
+        <select className={styles.select} value={cohort} onChange={(e) => { setCohort(e.target.value); setStudentId('') }}>
+          <option value="">Select a cohort…</option>
+          {cohorts.map((c) => <option key={c} value={c}>{c}</option>)}
+        </select>
+
+        {cohort && (
+          <>
+            <label className={styles.label}>Your name</label>
+            <select className={styles.select} value={studentId} onChange={(e) => setStudentId(e.target.value)}>
+              <option value="">Select your name…</option>
+              {roster.map((s) => <option key={s.student_id} value={s.student_id}>{s.display_name}</option>)}
+            </select>
+          </>
+        )}
+
+        <button className={styles.primaryBtn} disabled={!studentId || loading} onClick={handleLogin}>
+          {loading ? 'Signing in…' : 'Continue'}
+        </button>
+      </div>
+    </div>
+  )
+}

frontend/src/platform/MyLearningTab.jsx

@@ -0,0 +1,135 @@
+import { useState, useEffect, useCallback, useRef } from 'react'
+import { api } from './api'
+import styles from './Platform.module.css'
+
+const POLL_MS = 2500
+
+// The original Phase 2A/2B "Up Next" + Launch Lab / Reset flow, now extended with overall
+// percent-complete (Phase 3B's rule-driven curriculum state, GET /api/curriculum/state, instead
+// of the older /api/curriculum/path stats-only shape — same stage list, richer per-stage data).
+export default function MyLearningTab() {
+  const [curriculum, setCurriculum] = useState(null)
+  const [envStatus, setEnvStatus] = useState(null)
+  const [error, setError] = useState(null)
+  const [busy, setBusy] = useState(false)
+  const pollRef = useRef(null)
+
+  const loadCurriculum = useCallback(() => {
+    api.curriculumState().then(setCurriculum).catch((e) => setError(e.message))
+  }, [])
+  const loadEnvStatus = useCallback(() => {
+    api.environmentStatus().then(setEnvStatus).catch((e) => setError(e.message))
+  }, [])
+
+  useEffect(() => { loadCurriculum(); loadEnvStatus() }, [loadCurriculum, loadEnvStatus])
+
+  useEffect(() => {
+    const inFlight = envStatus && ['requested', 'provisioning', 'resetting'].includes(envStatus.status)
+    if (inFlight && !pollRef.current) {
+      pollRef.current = setInterval(loadEnvStatus, POLL_MS)
+    } else if (!inFlight && pollRef.current) {
+      clearInterval(pollRef.current)
+      pollRef.current = null
+    }
+    return () => { if (pollRef.current) { clearInterval(pollRef.current); pollRef.current = null } }
+  }, [envStatus, loadEnvStatus])
+
+  const handleLaunch = async () => {
+    setBusy(true); setError(null)
+    try {
+      const result = await api.launchEnvironment()
+      setEnvStatus(result)
+      if (result.status === 'running' && result.launch_path) window.location.href = result.launch_path
+    } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+  const handleReset = async () => {
+    setBusy(true); setError(null)
+    try { setEnvStatus(await api.resetEnvironment()) } catch (e) { setError(e.message) } finally { setBusy(false) }
+  }
+
+  const currentStage = curriculum?.stages?.find((s) => s.id === curriculum.current_stage)
+
+  return (
+    <>
+      {error && <div className={styles.errorBox}>{error}</div>}
+
+      <section className={styles.card}>
+        <h2>Current Stage</h2>
+        {!curriculum ? <p className={styles.muted}>Loading curriculum…</p> : (
+          <>
+            <div style={{ marginBottom: '0.75rem' }}>
+              <div style={{ display: 'flex', justifyContent: 'space-between', fontSize: '0.85rem', marginBottom: '0.3rem' }}>
+                <span>Overall progress</span><span className={styles.muted}>{curriculum.percent_complete}%</span>
+              </div>
+              <div className={styles.progressBarTrack}><div className={styles.progressBarFill} style={{ width: `${curriculum.percent_complete}%` }} /></div>
+            </div>
+            <div className={styles.stageRow}>
+              {curriculum.stages.map((s) => (
+                <div key={s.id} className={`${styles.stagePill} ${s.id === curriculum.current_stage ? styles.stagePillActive : ''} ${s.locked ? styles.stagePillLocked : ''}`}>
+                  <span>{s.icon}</span> {s.name}
+                  <span className={styles.stageCount}>{s.completed}/{s.total}</span>
+                </div>
+              ))}
+            </div>
+            {currentStage ? (
+              <p className={styles.nextUp}>
+                Up next: <strong>{currentStage.name}</strong>
+                {currentStage.next_scenario && <> — {currentStage.next_scenario}</>}
+              </p>
+            ) : (
+              <p className={styles.nextUp}>All curriculum stages complete — your Capstone is waiting.</p>
+            )}
+          </>
+        )}
+      </section>
+
+      <section className={styles.card}>
+        <h2>Your Lab</h2>
+        <EnvironmentPanel status={envStatus} busy={busy} onLaunch={handleLaunch} onReset={handleReset} />
+      </section>
+    </>
+  )
+}
+
+function EnvironmentPanel({ status, busy, onLaunch, onReset }) {
+  const s = status?.status || 'none'
+
+  if (s === 'none' || s === 'destroyed') {
+    return (
+      <>
+        <p className={styles.muted}>No lab running yet.</p>
+        <button className={styles.primaryBtn} disabled={busy} onClick={onLaunch}>
+          {busy ? 'Launching…' : 'Launch Lab'}
+        </button>
+      </>
+    )
+  }
+  if (['requested', 'provisioning', 'resetting'].includes(s)) {
+    return <p className={styles.statusLine}><span className={styles.spinner} /> {s === 'resetting' ? 'Recreating your lab…' : 'Starting your lab…'}</p>
+  }
+  if (s === 'running') {
+    return (
+      <>
+        <p className={styles.statusLine}><span className={styles.dotOk} /> Lab ready.</p>
+        <div className={styles.btnRow}>
+          <a className={styles.primaryBtn} href={`${status.launch_path}`}>Continue Lab</a>
+          <button className={styles.secondaryBtn} disabled={busy} onClick={onReset}>
+            {busy ? 'Working…' : 'Recreate Lab'}
+          </button>
+        </div>
+        <p className={styles.hint}>Recreating gives you a clean environment. Your progress is saved separately and is never lost.</p>
+      </>
+    )
+  }
+  if (s === 'error') {
+    return (
+      <>
+        <p className={styles.statusLine}><span className={styles.dotErr} /> {status.error_reason || 'Your lab hit a problem.'}</p>
+        <button className={styles.primaryBtn} disabled={busy} onClick={onLaunch}>
+          {busy ? 'Launching…' : 'Try Again'}
+        </button>
+      </>
+    )
+  }
+  return <p className={styles.muted}>Unknown state ({s}).</p>
+}

frontend/src/platform/Platform.module.css

@@ -0,0 +1,183 @@
+/* Platform Shell styling — reuses the existing design tokens from index.css (--bg, --surface,
+   --green, --text, etc.) so the entry/dashboard screens feel like the same product as the Lab
+   UI, not a bolted-on separate app. */
+
+.entryWrap {
+  height: 100vh;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: var(--bg);
+  font-family: var(--sans);
+  color: var(--text);
+}
+
+.entryCard {
+  width: 380px;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  padding: 2rem;
+}
+
+.brand {
+  font-family: var(--mono);
+  font-size: 1.3rem;
+  font-weight: 600;
+  color: var(--green);
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+}
+.brandIcon { font-size: 1.4rem; }
+
+.tagline { color: var(--text-2); margin: 0.5rem 0 0.25rem; font-size: 0.9rem; }
+.pilotNote { color: var(--text-3); font-size: 0.75rem; margin-bottom: 1.25rem; }
+
+.label { display: block; font-size: 0.8rem; color: var(--text-2); margin: 0.9rem 0 0.3rem; }
+
+.select {
+  width: 100%;
+  padding: 0.55rem 0.6rem;
+  background: var(--surface2);
+  border: 1px solid var(--border2);
+  border-radius: var(--radius);
+  color: var(--text);
+  font-family: var(--sans);
+  font-size: 0.9rem;
+}
+
+.primaryBtn {
+  margin-top: 1.25rem;
+  width: 100%;
+  padding: 0.65rem 1rem;
+  background: var(--green);
+  color: #05130a;
+  border: none;
+  border-radius: var(--radius);
+  font-weight: 600;
+  font-size: 0.9rem;
+  cursor: pointer;
+  text-align: center;
+  text-decoration: none;
+  display: inline-block;
+}
+.primaryBtn:disabled { opacity: 0.5; cursor: not-allowed; }
+
+.secondaryBtn {
+  padding: 0.65rem 1rem;
+  background: transparent;
+  color: var(--text);
+  border: 1px solid var(--border2);
+  border-radius: var(--radius);
+  font-size: 0.9rem;
+  cursor: pointer;
+}
+.secondaryBtn:disabled { opacity: 0.5; cursor: not-allowed; }
+
+.linkBtn {
+  background: none;
+  border: none;
+  color: var(--text-2);
+  font-size: 0.85rem;
+  cursor: pointer;
+  text-decoration: underline;
+}
+
+.errorBox {
+  background: var(--red-dim);
+  color: var(--red);
+  border: 1px solid var(--red);
+  border-radius: var(--radius);
+  padding: 0.6rem 0.8rem;
+  font-size: 0.85rem;
+  margin-bottom: 1rem;
+}
+
+/* ── Dashboard ─────────────────────────────────────────────────────────── */
+
+.dashWrap {
+  min-height: 100vh;
+  background: var(--bg);
+  color: var(--text);
+  font-family: var(--sans);
+  padding: 0 0 3rem;
+}
+
+.dashHeader {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 1.1rem 2rem;
+  border-bottom: 1px solid var(--border);
+}
+.headerRight { display: flex; align-items: center; gap: 1rem; }
+.studentName { font-weight: 600; }
+
+.card {
+  max-width: 760px;
+  margin: 1.5rem auto 0;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  padding: 1.5rem;
+}
+.card h2 { font-size: 1rem; margin-bottom: 1rem; color: var(--text); }
+
+.muted { color: var(--text-2); font-size: 0.9rem; }
+
+.stageRow { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 0.75rem; }
+.stagePill {
+  display: flex; align-items: center; gap: 0.4rem;
+  padding: 0.4rem 0.7rem;
+  background: var(--surface2);
+  border: 1px solid var(--border2);
+  border-radius: 999px;
+  font-size: 0.8rem;
+  color: var(--text-2);
+}
+.stagePillActive { border-color: var(--green); color: var(--text); }
+.stagePillLocked { opacity: 0.5; }
+.stageCount { color: var(--text-3); font-family: var(--mono); font-size: 0.75rem; }
+
+.nextUp { font-size: 0.9rem; color: var(--text); }
+
+.statusLine { display: flex; align-items: center; gap: 0.5rem; font-size: 0.9rem; margin-bottom: 0.9rem; }
+.btnRow { display: flex; gap: 0.75rem; }
+.hint { color: var(--text-3); font-size: 0.78rem; margin-top: 0.75rem; }
+
+.dotOk, .dotErr { width: 8px; height: 8px; border-radius: 50%; display: inline-block; }
+.dotOk { background: var(--green); }
+.dotErr { background: var(--red); }
+
+.spinner {
+  width: 12px; height: 12px;
+  border: 2px solid var(--border2);
+  border-top-color: var(--green);
+  border-radius: 50%;
+  display: inline-block;
+  animation: spin 0.7s linear infinite;
+}
+@keyframes spin { to { transform: rotate(360deg); } }
+
+/* ── Learning tabs (Phase 3B) ─────────────────────────────────────────── */
+
+.tabNav { display: flex; gap: 1.25rem; padding: 0 2rem; border-bottom: 1px solid var(--border); }
+.tab { color: var(--text-2); cursor: pointer; font-size: 0.9rem; background: none; border: none; padding: 0.75rem 0; }
+.tabActive { color: var(--green); border-bottom: 2px solid var(--green); }
+
+.progressBarTrack { background: var(--surface3); border-radius: 4px; height: 8px; overflow: hidden; }
+.progressBarFill { background: var(--green); height: 8px; }
+
+table.dataTable { width: 100%; border-collapse: collapse; font-size: 0.85rem; }
+.dataTable th { text-align: left; color: var(--text-2); font-weight: 600; padding: 0.4rem 0.5rem; border-bottom: 1px solid var(--border2); font-size: 0.72rem; text-transform: uppercase; }
+.dataTable td { padding: 0.5rem 0.5rem; border-bottom: 1px solid var(--border); }
+
+.pill { display: inline-block; padding: 0.15rem 0.55rem; border-radius: 999px; font-size: 0.75rem; font-family: var(--mono); }
+.pillOk { background: var(--green-dim); color: var(--green); }
+.pillWarn { background: var(--amber-dim); color: var(--amber); }
+.pillErr { background: var(--red-dim); color: var(--red); }
+.pillMuted { background: var(--surface3); color: var(--text-2); }
+
+.lockedBox { text-align: center; padding: 2rem 1rem; color: var(--text-2); }
+.checklistItem { display: flex; align-items: center; gap: 0.5rem; padding: 0.35rem 0; font-size: 0.88rem; }

frontend/src/platform/PlatformShell.jsx

@@ -0,0 +1,28 @@
+import { useState, useEffect } from 'react'
+import { api, getCachedDisplay } from './api'
+import EntryScreen from './EntryScreen'
+import StudentDashboard from './StudentDashboard'
+
+// Top-level Platform Shell: entry screen if no valid session, dashboard otherwise. Session
+// validity is decided by the server (GET /api/session/whoami against the rn_session cookie),
+// not by anything read from localStorage/sessionStorage — those only cache the display name
+// for a snappier first paint, per api.js.
+export default function PlatformShell() {
+  const [student, setStudent] = useState(null)
+  const [checking, setChecking] = useState(true)
+
+  useEffect(() => {
+    const cached = getCachedDisplay()
+    if (cached) setStudent(cached) // optimistic paint while we confirm with the server
+    api.whoami()
+      .then(({ student_id }) => {
+        if (!cached || cached.student_id !== student_id) setStudent({ student_id, display_name: cached?.display_name || student_id })
+      })
+      .catch(() => setStudent(null))
+      .finally(() => setChecking(false))
+  }, [])
+
+  if (checking) return null
+  if (!student) return <EntryScreen onLogin={setStudent} />
+  return <StudentDashboard student={student} onLogout={() => setStudent(null)} />
+}

frontend/src/platform/PracticeTab.jsx

@@ -0,0 +1,77 @@
+import { useState, useEffect } from 'react'
+import { api } from './api'
+import styles from './Platform.module.css'
+
+// Available/completed scenarios (from curriculum state) + recent attempt history
+// (GET /api/attempts/recent) — purely informational, no controls here; the actual work happens
+// inside the Lab itself once launched from My Learning.
+export default function PracticeTab() {
+  const [curriculum, setCurriculum] = useState(null)
+  const [attempts, setAttempts] = useState(null)
+  const [error, setError] = useState(null)
+
+  useEffect(() => {
+    api.curriculumState().then(setCurriculum).catch((e) => setError(e.message))
+    api.recentAttempts().then(setAttempts).catch((e) => setError(e.message))
+  }, [])
+
+  const allScenarios = curriculum?.stages.flatMap((s) => Array(s.total).fill(null).map((_, i) => i)) || []
+  const completedCount = curriculum?.stages.reduce((n, s) => n + s.completed, 0) || 0
+  const totalCount = allScenarios.length
+
+  return (
+    <>
+      {error && <div className={styles.errorBox}>{error}</div>}
+      <section className={styles.card}>
+        <h2>Scenarios</h2>
+        {!curriculum ? <p className={styles.muted}>Loading…</p> : (
+          <table className={styles.dataTable}>
+            <thead><tr><th>Stage</th><th>Completed</th><th>Status</th></tr></thead>
+            <tbody>
+              {curriculum.stages.map((s) => (
+                <tr key={s.id}>
+                  <td>{s.icon} {s.name}</td>
+                  <td>{s.completed}/{s.total}</td>
+                  <td>
+                    {s.locked ? <span className={`${styles.pill} ${styles.pillMuted}`}>locked</span>
+                      : s.complete ? <span className={`${styles.pill} ${styles.pillOk}`}>complete</span>
+                      : <span className={`${styles.pill} ${styles.pillWarn}`}>in progress</span>}
+                  </td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+        {curriculum && <p className={styles.hint} style={{ marginTop: '0.75rem' }}>{completedCount}/{totalCount} scenarios completed overall.</p>}
+      </section>
+
+      <section className={styles.card}>
+        <h2>Recent Attempts</h2>
+        {!attempts ? <p className={styles.muted}>Loading…</p> : attempts.length === 0 ? <p className={styles.muted}>No attempts yet — launch your Lab and pick a scenario.</p> : (
+          <table className={styles.dataTable}>
+            <thead><tr><th>Scenario</th><th>Status</th><th>Validations</th><th>Hints</th><th>Duration</th></tr></thead>
+            <tbody>
+              {attempts.map((a, i) => (
+                <tr key={i}>
+                  <td>{a.scenario_id}</td>
+                  <td>
+                    {a.status === 'completed' ? <span className={`${styles.pill} ${styles.pillOk}`}>completed</span>
+                      : <span className={`${styles.pill} ${styles.pillWarn}`}>in progress</span>}
+                  </td>
+                  <td>{a.validation_pass_count} passed, {a.validation_fail_count} failed</td>
+                  <td>{a.hint_count || 0}</td>
+                  <td>{a.duration_seconds ? formatDuration(a.duration_seconds) : '—'}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        )}
+      </section>
+    </>
+  )
+}
+
+function formatDuration(seconds) {
+  const m = Math.floor(seconds / 60), s = seconds % 60
+  return `${m}m ${s}s`
+}

frontend/src/platform/StudentDashboard.jsx

@@ -0,0 +1,50 @@
+import { useState } from 'react'
+import { api } from './api'
+import styles from './Platform.module.css'
+import MyLearningTab from './MyLearningTab'
+import PracticeTab from './PracticeTab'
+import AssessmentsTab from './AssessmentsTab'
+import CapstoneTab from './CapstoneTab'
+import AchievementsTab from './AchievementsTab'
+
+const TABS = [
+  { key: 'learning', label: 'My Learning' },
+  { key: 'practice', label: 'Practice' },
+  { key: 'assessments', label: 'Assessments' },
+  { key: 'capstone', label: 'Capstone' },
+  { key: 'achievements', label: 'Achievements' },
+]
+
+// Student home — tabbed as of Phase 3B (docs/PHASE3B_LEARNING_AND_ASSESSMENT.md §10): My
+// Learning (the original Phase 2A/2B "Up Next" + Lab launch flow, unchanged in behavior, just
+// extracted into its own component), Practice, Assessments, Capstone, Achievements/History.
+export default function StudentDashboard({ student, onLogout }) {
+  const [tab, setTab] = useState('learning')
+  const handleLogout = () => { api.logout().then(onLogout) }
+
+  return (
+    <div className={styles.dashWrap}>
+      <header className={styles.dashHeader}>
+        <div className={styles.brand}><span className={styles.brandIcon}>⎈</span> RootNode Academy</div>
+        <div className={styles.headerRight}>
+          <span className={styles.studentName}>{student.display_name}</span>
+          <button className={styles.linkBtn} onClick={handleLogout}>Sign out</button>
+        </div>
+      </header>
+
+      <nav className={styles.tabNav}>
+        {TABS.map((t) => (
+          <button key={t.key} className={`${styles.tab} ${tab === t.key ? styles.tabActive : ''}`} onClick={() => setTab(t.key)}>
+            {t.label}
+          </button>
+        ))}
+      </nav>
+
+      {tab === 'learning' && <MyLearningTab />}
+      {tab === 'practice' && <PracticeTab />}
+      {tab === 'assessments' && <AssessmentsTab />}
+      {tab === 'capstone' && <CapstoneTab />}
+      {tab === 'achievements' && <AchievementsTab />}
+    </div>
+  )
+}

frontend/src/platform/api.js

@@ -0,0 +1,86 @@
+// Platform Shell API client. Identity is a server-controlled session cookie (rn_session,
+// HttpOnly — this code can't read it, and doesn't need to; the browser sends it automatically
+// on every same-origin request). Roster name-picking is classroom/pilot identification, not
+// production authentication (see docs/PHASE3A_IDENTITY_AND_INSTRUCTOR_ACCESS.md §5) — what's
+// hardened here is the session that results from it: persistent (survives an API restart),
+// unforgeable, and checked on every request.
+//
+// display_name is still cached in sessionStorage purely for UI convenience (showing "Hi,
+// Alice" without an extra round trip) — it carries no authority; every actual API call is
+// authorized by the cookie alone, not by anything read from here.
+//
+// rn_csrf_s is a deliberately non-HttpOnly cookie (double-submit CSRF pattern) — this code
+// reads it and echoes it back as a header on every state-changing request, proving the request
+// came from our own origin's JS (a cross-origin attacker can trigger the cookie but can't read
+// its value or attach a matching custom header without CORS, which we don't grant elsewhere).
+
+const DISPLAY_CACHE_KEY = 'rootnode_student_display'
+const CSRF_COOKIE = 'rn_csrf_s'
+
+export function getCachedDisplay() {
+  try { return JSON.parse(sessionStorage.getItem(DISPLAY_CACHE_KEY) || 'null') } catch { return null }
+}
+function cacheDisplay(student) {
+  sessionStorage.setItem(DISPLAY_CACHE_KEY, JSON.stringify(student))
+}
+function clearCachedDisplay() {
+  sessionStorage.removeItem(DISPLAY_CACHE_KEY)
+}
+
+function getCookie(name) {
+  return document.cookie.split('; ').find((c) => c.startsWith(`${name}=`))?.split('=')[1]
+}
+
+async function json(res) {
+  if (!res.ok) {
+    const body = await res.json().catch(() => ({}))
+    throw new Error(body.message || body.error || `Request failed (${res.status})`)
+  }
+  return res.json()
+}
+
+function mutate(path, body) {
+  return fetch(path, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json', 'X-CSRF-Token': getCookie(CSRF_COOKIE) || '' },
+    body: body ? JSON.stringify(body) : undefined,
+  }).then(json)
+}
+
+export const api = {
+  cohorts: () => fetch('/api/roster/cohorts').then(json),
+  roster: (cohort) => fetch(`/api/roster?cohort=${encodeURIComponent(cohort)}`).then(json),
+  login: async (student_id) => {
+    // No CSRF token yet at login (nothing authenticated to forge into) — same reasoning as the
+    // instructor login route.
+    const student = await fetch('/api/login', {
+      method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ student_id }),
+    }).then(json)
+    cacheDisplay(student)
+    return student
+  },
+  logout: async () => {
+    await mutate('/api/logout').catch(() => {})
+    clearCachedDisplay()
+  },
+  whoami: () => fetch('/api/session/whoami').then(json),
+
+  curriculumPath: () => fetch('/api/curriculum/path').then(json),
+  curriculumState: () => fetch('/api/curriculum/state').then(json),
+
+  environmentStatus: () => fetch('/api/environment/status').then(json),
+  launchEnvironment: () => mutate('/api/environment/launch'),
+  resetEnvironment: () => mutate('/api/environment/reset'),
+
+  recentAttempts: () => fetch('/api/attempts/recent').then(json),
+
+  assessments: () => fetch('/api/assessments').then(json),
+  activeAssessment: () => fetch('/api/assessments/active').then(json),
+  assessmentDetail: (sessionId) => fetch(`/api/assessments/${sessionId}`).then(json),
+  startAssessment: (definitionId) => mutate(`/api/assessments/${definitionId}/start`),
+  submitAssessment: (sessionId) => mutate(`/api/assessments/${sessionId}/submit`),
+
+  capstone: () => fetch('/api/capstone').then(json),
+
+  achievements: () => fetch('/api/achievements').then(json),
+}

infra/.gitignore

@@ -0,0 +1,34 @@
+# Never commit filled secrets — only *.env.template files are tracked.
+*.env
+!*.env.template
+
+# Docker TLS material — CA/server/client certs and keys, generated by
+# infra/scripts/docker-tls/generate-ca.sh and friends. Templates/READMEs stay tracked.
+docker/tls/*.pem
+docker/tls/*.key
+docker/tls/*.crt
+docker/tls/*.srl
+!docker/tls/**/README.md
+
+# Ansible Vault password files and any decrypted vars
+ansible/.vault_pass
+ansible/**/vault_plain.yml
+
+# Terraform/OpenTofu state and generated vars (may contain resource IDs/IPs)
+# Phase 4.1: these patterns were previously written repo-root-relative (e.g.
+# "infra/terraform/...") inside THIS file, which git resolves relative to the .gitignore's own
+# directory (infra/) — so they silently matched nothing at all. Found via `git status` showing
+# a real .terraform/ provider cache as untracked when it should have been ignored. Fixed by
+# dropping the redundant leading "infra/" from every pattern below.
+terraform/**/*.tfstate
+terraform/**/*.tfstate.*
+terraform/**/.terraform/
+terraform/**/terraform.tfvars
+!terraform/**/terraform.tfvars.example
+
+# Backup output and restore scratch space
+backup/output/
+backup/restore-test/
+
+# Load test results (local artifacts, not source)
+scripts/loadtest/results/

infra/ansible/ansible.cfg

@@ -0,0 +1,10 @@
+[defaults]
+inventory = inventory/production.ini
+roles_path = roles
+host_key_checking = True
+retry_files_enabled = False
+stdout_callback = yaml
+
+[privilege_escalation]
+become = True
+become_method = sudo

infra/ansible/group_vars/production.vault.yml.template

@@ -0,0 +1,22 @@
+# Ansible Vault template — copy to production.vault.yml and encrypt it, NEVER commit the
+# plaintext or the encrypted file to git (infra/.gitignore already excludes
+# **/vault_plain.yml; the encrypted production.vault.yml itself is small/safe to commit IF
+# encrypted — see docs/PRODUCTION_DEPLOYMENT.md §10 for the actual decision made). Ansible
+# Vault chosen over SOPS/age here because it's already bundled with Ansible (no new tool to
+# install/trust) and this project's secret surface is small enough that Vault's simplicity
+# outweighs SOPS's per-key-value granularity — revisit if that changes.
+#
+#   cp production.vault.yml.template production.vault.yml
+#   # fill in real values below
+#   ansible-vault encrypt production.vault.yml
+#
+# Reference a vaulted value from group_vars/production.yml or a role like:
+#   postgres_password: "{{ vault_postgres_password }}"
+
+vault_postgres_password: __REPLACE__
+vault_provisioner_shared_secret: __REPLACE_openssl_rand_hex_32__
+vault_owner_bootstrap_password: __REPLACE__          # used once, by a human, per docs/RUNBOOK_FIRST_DEPLOYMENT.md
+vault_postgres_exporter_password: __REPLACE__
+vault_backup_encryption_passphrase: __REPLACE_openssl_rand_base64_32__
+vault_backup_offsite_credentials: __REPLACE_e.g._Hetzner_Storage_Box_ssh_key_passphrase_or_S3_secret_key__
+vault_grafana_admin_password: __REPLACE__

infra/ansible/group_vars/production.yml

@@ -0,0 +1,33 @@
+# Production variables — referenced by every {{ }} placeholder in infra/docker/, infra/firewall/,
+# and the roles below. Fill in the __PLACEHOLDER__ values once the real server exists
+# (docs/PRODUCTION_DEPLOYMENT.md §1). Nothing here is a secret — real secrets live in
+# infra/environments/production/*.env (gitignored) and Ansible Vault (see
+# infra/ansible/group_vars/production.vault.yml.template), never in this plain-vars file.
+
+env: production
+academy_domain: __REPLACE_e.g._academy.rootnode.example__
+
+# ── Network topology (Phase 4 §5 — placeholders until real hardware exists) ────────────────
+platform_ip: __PLATFORM_VM_IP__
+lab_host_ip: __LAB_HOST_VM_IP__
+management_cidr: __YOUR_ADMIN_ACCESS_CIDR__       # e.g. a VPN/WireGuard subnet, never 0.0.0.0/0
+proxmox_mgmt_cidr: __PROXMOX_HOST_MGMT_CIDR__
+lab_subnet_range: "10.42.0.0/16"                    # matches NO_PROXY_CIDRS already used by the app
+lab_router_port: "8443"                             # Gateway -> Lab Host Router (data plane) — see docs/PHASE4_1_PREPRODUCTION_HARDENING.md §1-3
+
+# ── Storage (Phase 4 §4 — a decision framework, not a final layout; see docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md §4)
+rootnode_data_root: /srv/rootnode-data   # expected to be a ZFS dataset mountpoint on the real host
+
+# ── Registry / images (infra/docker/IMAGE_STRATEGY.md) ─────────────────────────────────────
+registry: git.synthossystems.com
+image_tag: __GIT_SHA_OR_RELEASE_TAG__
+
+postgres_exporter_user: rootnode_exporter
+
+# ── Observability (infra/monitoring/) ───────────────────────────────────────────────────────
+prometheus_retention_days: 30
+alertmanager_webhook_url: __REPLACE_e.g._uptime_kuma_or_ntfy_webhook__
+
+# ── Backup (infra/backup/) ───────────────────────────────────────────────────────────────────
+backup_retention_days: 30
+backup_offsite_target: __REPLACE_e.g._Hetzner_Storage_Box_path_or_S3_bucket__

infra/ansible/group_vars/staging.yml

@@ -0,0 +1,22 @@
+# Staging variables — same shape as production.yml, lower stakes. See
+# infra/environments/staging/README.md.
+
+env: staging
+academy_domain: __REPLACE_e.g._staging.academy.rootnode.example_or_unset_for_no_public_TLS__
+
+platform_ip: __STAGING_PLATFORM_IP__
+lab_host_ip: __STAGING_LAB_HOST_IP__
+management_cidr: __YOUR_ADMIN_ACCESS_CIDR__
+proxmox_mgmt_cidr: __PROXMOX_HOST_MGMT_CIDR__
+lab_subnet_range: "10.42.0.0/16"
+
+rootnode_data_root: /srv/rootnode-data-staging
+
+registry: git.synthossystems.com
+image_tag: __STAGING_TAG_e.g._staging-<sha>__
+
+prometheus_retention_days: 7
+alertmanager_webhook_url: __OPTIONAL_staging_can_skip_alerting__
+
+backup_retention_days: 7
+backup_offsite_target: __OPTIONAL_staging_backups_are_lower_priority__

infra/ansible/inventory/production.ini

@@ -0,0 +1,16 @@
+# Production inventory. IPs/hostnames are placeholders — fill in once the real VMs exist
+# (docs/PRODUCTION_DEPLOYMENT.md §1). This file is safe to commit (no secrets, just topology).
+
+[platform]
+rn-platform-01 ansible_host=__PLATFORM_VM_IP__
+
+[lab_host]
+rn-lab-host-01 ansible_host=__LAB_HOST_VM_IP__
+
+[rootnode:children]
+platform
+lab_host
+
+[rootnode:vars]
+ansible_user=rootnode-deploy
+ansible_ssh_common_args='-o StrictHostKeyChecking=yes'

infra/ansible/inventory/staging.ini

@@ -0,0 +1,16 @@
+# Staging inventory — same group shape as production, pointed at homelab VMs/containers or a
+# resource-constrained slice of the dedicated server once it exists (infra/environments/staging/README.md).
+
+[platform]
+rn-platform-staging ansible_host=__STAGING_PLATFORM_IP__
+
+[lab_host]
+rn-lab-host-staging ansible_host=__STAGING_LAB_HOST_IP__
+
+[rootnode:children]
+platform
+lab_host
+
+[rootnode:vars]
+ansible_user=rootnode-deploy
+env=staging

infra/ansible/roles/backup/tasks/main.yml

@@ -0,0 +1,63 @@
+---
+# Deploys the backup script + a daily cron job on rn-platform-01. The script itself
+# (infra/backup/backup-postgres.sh) is identical to what infra/backup/test-backup-restore.sh
+# exercises locally — same code path, just pointed at real production values here.
+
+- name: Install postgresql-client + gpg (backup script dependencies)
+  ansible.builtin.apt:
+    name: [postgresql-client, gnupg]
+    state: present
+
+- name: Create backup directories
+  ansible.builtin.file:
+    path: "{{ item }}"
+    state: directory
+    owner: root
+    group: root
+    mode: "0700"
+  loop:
+    - /opt/rootnode/backup
+    - "{{ rootnode_data_root }}/backups"
+
+- name: Deploy backup script
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../backup/backup-postgres.sh"
+    dest: /opt/rootnode/backup/backup-postgres.sh
+    mode: "0750"
+
+- name: Deploy restore + verify scripts (not run by cron, kept alongside for the runbook)
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../backup/{{ item }}"
+    dest: "/opt/rootnode/backup/{{ item }}"
+    mode: "0750"
+  loop:
+    - restore-postgres.sh
+    - verify-restore.sh
+
+- name: Deploy the backup env file (PLATFORM_DB_URL, encryption passphrase, offsite target)
+  ansible.builtin.template:
+    src: backup.env.j2
+    dest: /etc/rootnode/backup.env
+    owner: root
+    group: root
+    mode: "0600"
+
+- name: Deploy cron wrapper (sources the env file, writes to syslog too)
+  ansible.builtin.template:
+    src: run-backup.sh.j2
+    dest: /opt/rootnode/backup/run-backup.sh
+    mode: "0750"
+
+- name: Install daily backup cron job
+  ansible.builtin.cron:
+    name: rootnode-postgres-backup
+    user: root
+    minute: "15"
+    hour: "3"
+    job: /opt/rootnode/backup/run-backup.sh
+
+- name: Ensure node-exporter's textfile collector directory exists (backup metrics land here)
+  ansible.builtin.file:
+    path: /var/lib/node-exporter/textfile
+    state: directory
+    mode: "0755"

infra/ansible/roles/backup/templates/backup.env.j2

@@ -0,0 +1,6 @@
+PLATFORM_DB_URL=postgres://rootnode_platform:{{ vault_postgres_password }}@localhost:5432/rootnode_platform
+BACKUP_DIR={{ rootnode_data_root }}/backups
+BACKUP_ENCRYPTION_PASSPHRASE={{ vault_backup_encryption_passphrase }}
+BACKUP_RETENTION_DAYS={{ backup_retention_days }}
+BACKUP_OFFSITE_TARGET={{ backup_offsite_target }}
+METRICS_TEXTFILE_DIR=/var/lib/node-exporter/textfile

infra/ansible/roles/backup/templates/run-backup.sh.j2

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# Cron wrapper — sources the deployed env file and runs the real backup script, logging to
+# syslog (visible via journalctl and shipped to Loki by promtail like every other unit) in
+# addition to whatever cron itself captures.
+set -euo pipefail
+set -a
+source /etc/rootnode/backup.env
+set +a
+exec /opt/rootnode/backup/backup-postgres.sh 2>&1 | systemd-cat -t rootnode-backup

infra/ansible/roles/common/defaults/main.yml

@@ -0,0 +1,3 @@
+---
+common_timezone: UTC
+common_unattended_upgrades: true

infra/ansible/roles/common/tasks/docker-engine.yml

@@ -0,0 +1,35 @@
+---
+# Shared Docker Engine install — used by both platform and lab-host roles (import_tasks from
+# common, not duplicated). Follows Docker's own official apt-repo installation method.
+
+- name: Add Docker's GPG key
+  ansible.builtin.get_url:
+    url: https://download.docker.com/linux/ubuntu/gpg
+    dest: /etc/apt/keyrings/docker.asc
+    mode: "0644"
+  register: docker_gpg
+  retries: 3
+  delay: 5
+  until: docker_gpg is succeeded
+
+- name: Add Docker apt repository
+  ansible.builtin.apt_repository:
+    repo: "deb [arch={{ ansible_architecture | replace('x86_64','amd64') }} signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu {{ ansible_distribution_release }} stable"
+    state: present
+    filename: docker
+
+- name: Install Docker Engine + Compose plugin
+  ansible.builtin.apt:
+    name:
+      - docker-ce
+      - docker-ce-cli
+      - containerd.io
+      - docker-compose-plugin
+    state: present
+    update_cache: true
+
+- name: Enable and start Docker
+  ansible.builtin.systemd:
+    name: docker
+    enabled: true
+    state: started

infra/ansible/roles/common/tasks/main.yml

@@ -0,0 +1,58 @@
+---
+# Baseline hardening applied to both rn-platform-01 and rn-lab-host-01 before anything
+# RootNode-specific — idempotent, safe to re-run (Phase 4 §20 requirement).
+
+- name: Set timezone
+  community.general.timezone:
+    name: "{{ common_timezone }}"
+
+- name: Install base packages
+  ansible.builtin.apt:
+    name:
+      - curl
+      - ca-certificates
+      - gnupg
+      - iptables
+      - iptables-persistent
+      - unattended-upgrades
+      - fail2ban
+      - jq
+    state: present
+    update_cache: true
+    cache_valid_time: 3600
+
+- name: Enable unattended security upgrades
+  ansible.builtin.copy:
+    dest: /etc/apt/apt.conf.d/20auto-upgrades
+    content: |
+      APT::Periodic::Update-Package-Lists "1";
+      APT::Periodic::Unattended-Upgrade "1";
+    mode: "0644"
+  when: common_unattended_upgrades
+
+- name: Create the rootnode-deploy service account (if not the connecting user already)
+  ansible.builtin.user:
+    name: rootnode-deploy
+    shell: /bin/bash
+    groups: docker
+    append: true
+    create_home: true
+  register: deploy_user_result
+  failed_when: false   # non-fatal — some hosts may already use this as ansible_user
+
+- name: Ensure fail2ban is enabled for SSH
+  ansible.builtin.service:
+    name: fail2ban
+    state: started
+    enabled: true
+
+- name: Create /opt/rootnode and /etc/rootnode base directories
+  ansible.builtin.file:
+    path: "{{ item }}"
+    state: directory
+    owner: root
+    group: root
+    mode: "0750"
+  loop:
+    - /opt/rootnode
+    - /etc/rootnode

infra/ansible/roles/docker-tls/defaults/main.yml

@@ -0,0 +1,6 @@
+---
+# Local path (on the machine running ansible-playbook, NOT on either VM) holding the cert
+# bundle generated by infra/scripts/docker-tls/generate-docker-tls.sh. The CA private key
+# (ca-key.pem) is deliberately never copied to either host by this role — only its public
+# ca.pem, plus the one cert/key pair each host actually needs.
+docker_tls_local_bundle_dir: "{{ lookup('env', 'ROOTNODE_TLS_BUNDLE_DIR') | default('/does/not/exist', true) }}"

infra/ansible/roles/docker-tls/handlers/main.yml

@@ -0,0 +1,22 @@
+---
+- name: restart docker with tls
+  ansible.builtin.systemd:
+    name: docker
+    state: restarted
+    daemon_reload: true
+
+# Phase 4.1 — these restart the whole per-host compose wrapper unit (no per-container systemd
+# units exist in this project's convention, see the `platform`/`lab-host` roles), which is
+# heavier than a surgical single-container restart but consistent with how every other
+# config-changed-so-restart-the-stack case is already handled here.
+- name: restart lab-router
+  ansible.builtin.systemd:
+    name: rootnode-lab-host.service
+    state: restarted
+  when: inventory_hostname in groups['lab_host']
+
+- name: restart gateway
+  ansible.builtin.systemd:
+    name: rootnode-platform.service
+    state: restarted
+  when: inventory_hostname in groups['platform']

infra/ansible/roles/docker-tls/tasks/main.yml

@@ -0,0 +1,136 @@
+---
+# Deploys Docker TLS material generated OFFLINE by infra/scripts/docker-tls/generate-docker-tls.sh
+# — this role never generates key material itself, and the CA private key never touches either
+# VM (see infra/docker/tls/README.md). Fails loudly if the operator forgot to set
+# ROOTNODE_TLS_BUNDLE_DIR / run the generation script first, rather than silently skipping and
+# leaving the Provisioner unable to reach rn-lab-host-01.
+
+- name: Verify the local TLS bundle directory exists
+  ansible.builtin.stat:
+    path: "{{ docker_tls_local_bundle_dir }}"
+  register: bundle_dir
+  delegate_to: localhost
+  become: false
+
+- name: Fail fast if the TLS bundle wasn't generated
+  ansible.builtin.fail:
+    msg: >-
+      ROOTNODE_TLS_BUNDLE_DIR ({{ docker_tls_local_bundle_dir }}) does not exist. Run
+      infra/scripts/docker-tls/generate-docker-tls.sh first, then re-run with
+      ROOTNODE_TLS_BUNDLE_DIR=<output dir> in the environment.
+  when: not bundle_dir.stat.exists
+
+- name: Create /etc/rootnode/docker-tls
+  ansible.builtin.file:
+    path: /etc/rootnode/docker-tls
+    state: directory
+    owner: root
+    group: root
+    mode: "0700"
+
+- name: Deploy CA cert (public, both hosts)
+  ansible.builtin.copy:
+    src: "{{ docker_tls_local_bundle_dir }}/ca.pem"
+    dest: /etc/rootnode/docker-tls/ca.pem
+    owner: root
+    group: root
+    mode: "0444"
+
+- name: Deploy server cert/key (rn-lab-host-01 only)
+  ansible.builtin.copy:
+    src: "{{ docker_tls_local_bundle_dir }}/{{ item.src }}"
+    dest: "/etc/rootnode/docker-tls/{{ item.dest }}"
+    owner: root
+    group: root
+    mode: "{{ item.mode }}"
+  loop:
+    - { src: server-cert.pem, dest: server-cert.pem, mode: "0444" }
+    - { src: server-key.pem, dest: server-key.pem, mode: "0400" }
+  when: inventory_hostname in groups['lab_host']
+  notify: restart docker with tls
+
+- name: Deploy Provisioner client cert/key (rn-platform-01 only)
+  ansible.builtin.copy:
+    src: "{{ docker_tls_local_bundle_dir }}/{{ item.src }}"
+    dest: "/etc/rootnode/docker-tls/{{ item.dest }}"
+    owner: root
+    group: root
+    mode: "{{ item.mode }}"
+  loop:
+    - { src: provisioner-client-cert.pem, dest: provisioner-client-cert.pem, mode: "0444" }
+    - { src: provisioner-client-key.pem, dest: provisioner-client-key.pem, mode: "0400" }
+  when: inventory_hostname in groups['platform']
+
+- name: Configure dockerd for TLS (rn-lab-host-01 only)
+  ansible.builtin.template:
+    src: daemon.json.j2
+    dest: /etc/docker/daemon.json
+    owner: root
+    group: root
+    mode: "0644"
+  when: inventory_hostname in groups['lab_host']
+  notify: restart docker with tls
+
+- name: Override the Docker systemd unit's ExecStart (clears the default -H fd:// flag)
+  ansible.builtin.file:
+    path: /etc/systemd/system/docker.service.d
+    state: directory
+    mode: "0755"
+  when: inventory_hostname in groups['lab_host']
+
+- name: Deploy the ExecStart override
+  ansible.builtin.template:
+    src: docker-override.conf.j2
+    dest: /etc/systemd/system/docker.service.d/override.conf
+    owner: root
+    group: root
+    mode: "0644"
+  when: inventory_hostname in groups['lab_host']
+  notify: restart docker with tls
+
+# ── Phase 4.1: the DATA-plane mTLS pair (Gateway <-> Lab Host Router). Same CA as the
+# CONTROL-plane pair above, separate directory (/etc/rootnode/lab-router-tls) so the two
+# concerns stay bind-mount-separable — the `lab-router`/`gateway` containers only ever need
+# their own pair mounted in, never the Docker TLS one. See
+# docs/PHASE4_1_PREPRODUCTION_HARDENING.md §1-3.
+- name: Create /etc/rootnode/lab-router-tls
+  ansible.builtin.file:
+    path: /etc/rootnode/lab-router-tls
+    state: directory
+    owner: root
+    group: root
+    mode: "0700"
+
+- name: Deploy CA cert for the data-plane pair (public, both hosts)
+  ansible.builtin.copy:
+    src: "{{ docker_tls_local_bundle_dir }}/ca.pem"
+    dest: /etc/rootnode/lab-router-tls/ca.pem
+    owner: root
+    group: root
+    mode: "0444"
+
+- name: Deploy Lab Host Router server cert/key (rn-lab-host-01 only)
+  ansible.builtin.copy:
+    src: "{{ docker_tls_local_bundle_dir }}/{{ item.src }}"
+    dest: "/etc/rootnode/lab-router-tls/{{ item.dest }}"
+    owner: root
+    group: root
+    mode: "{{ item.mode }}"
+  loop:
+    - { src: router-server-cert.pem, dest: router-server-cert.pem, mode: "0444" }
+    - { src: router-server-key.pem, dest: router-server-key.pem, mode: "0400" }
+  when: inventory_hostname in groups['lab_host']
+  notify: restart lab-router
+
+- name: Deploy Gateway client cert/key (rn-platform-01 only)
+  ansible.builtin.copy:
+    src: "{{ docker_tls_local_bundle_dir }}/{{ item.src }}"
+    dest: "/etc/rootnode/lab-router-tls/{{ item.dest }}"
+    owner: root
+    group: root
+    mode: "{{ item.mode }}"
+  loop:
+    - { src: gateway-client-cert.pem, dest: gateway-client-cert.pem, mode: "0444" }
+    - { src: gateway-client-key.pem, dest: gateway-client-key.pem, mode: "0400" }
+  when: inventory_hostname in groups['platform']
+  notify: restart gateway

infra/ansible/roles/docker-tls/templates/daemon.json.j2

@@ -0,0 +1,13 @@
+{
+  "tls": true,
+  "tlsverify": true,
+  "tlscacert": "/etc/rootnode/docker-tls/ca.pem",
+  "tlscert": "/etc/rootnode/docker-tls/server-cert.pem",
+  "tlskey": "/etc/rootnode/docker-tls/server-key.pem",
+  "hosts": ["unix:///var/run/docker.sock", "tcp://0.0.0.0:2376"],
+
+  "storage-driver": "overlay2",
+  "default-address-pools": [
+    { "base": "10.42.0.0/16", "size": 24 }
+  ]
+}

infra/ansible/roles/docker-tls/templates/docker-override.conf.j2

@@ -0,0 +1,7 @@
+# Docker's systemd unit specifies `-H fd://` on ExecStart by default, which conflicts with
+# setting `hosts` in daemon.json ("specified both as a flag and in the configuration file").
+# This override clears ExecStart and re-specifies it with no -H flag, letting daemon.json's
+# `hosts` list be the only source of truth — the documented fix for this exact conflict.
+[Service]
+ExecStart=
+ExecStart=/usr/bin/dockerd

infra/ansible/roles/firewall/handlers/main.yml

@@ -0,0 +1,4 @@
+---
+- name: reload firewall
+  ansible.builtin.command: netfilter-persistent reload
+  changed_when: true

infra/ansible/roles/firewall/tasks/main.yml

@@ -0,0 +1,28 @@
+---
+# Deploys the matching infra/firewall/*.rules file for this host's group and loads it. Same
+# ruleset, same variables as infra/firewall/validate-firewall.sh renders locally — this task
+# just uses Ansible's own templating instead of sed, against the real inventory values.
+
+- name: Determine which ruleset applies to this host
+  ansible.builtin.set_fact:
+    firewall_ruleset_name: "{{ 'rn-platform-01' if inventory_hostname in groups['platform'] else 'rn-lab-host-01' }}"
+
+- name: Render firewall ruleset for this host
+  ansible.builtin.template:
+    src: "{{ role_path }}/../../../firewall/{{ firewall_ruleset_name }}.rules"
+    dest: /etc/iptables/rules.v4.rootnode
+    owner: root
+    group: root
+    mode: "0600"
+  notify: reload firewall
+
+- name: Point iptables-persistent at the RootNode ruleset
+  ansible.builtin.file:
+    src: /etc/iptables/rules.v4.rootnode
+    dest: /etc/iptables/rules.v4
+    state: link
+    force: true
+  notify: reload firewall
+
+- name: Flush handlers so the firewall is active before later roles assume it
+  ansible.builtin.meta: flush_handlers

infra/ansible/roles/lab-host/handlers/main.yml

@@ -0,0 +1,6 @@
+---
+- name: restart rootnode-lab-host
+  ansible.builtin.systemd:
+    name: rootnode-lab-host
+    state: restarted
+    daemon_reload: true

infra/ansible/roles/lab-host/tasks/main.yml

@@ -0,0 +1,72 @@
+---
+# rn-lab-host-01: Docker Engine (TLS config comes from the docker-tls role, run before this
+# one), the egress proxy + monitoring agents compose stack, kernel prerequisites for nested
+# k3s in privileged Lab containers, and Docker daemon storage/limits configuration.
+
+- name: Install Docker Engine
+  ansible.builtin.import_tasks: "{{ role_path }}/../common/tasks/docker-engine.yml"
+
+- name: Kernel prerequisites for nested k3s (privileged containers)
+  ansible.posix.sysctl:
+    name: "{{ item.name }}"
+    value: "{{ item.value }}"
+    sysctl_set: true
+    state: present
+    reload: true
+  loop:
+    - { name: net.ipv4.ip_forward, value: "1" }
+    - { name: fs.inotify.max_user_watches, value: "524288" }   # k3s/kubelet watch a lot of files
+    - { name: fs.inotify.max_user_instances, value: "512" }
+    - { name: vm.max_map_count, value: "262144" }               # matches upstream k3s/etcd guidance
+
+- name: Ensure cgroup v2 controllers needed by nested k3s are available
+  ansible.builtin.command: cat /sys/fs/cgroup/cgroup.controllers
+  register: cgroup_controllers
+  changed_when: false
+  failed_when: false
+
+- name: Warn if cgroup v2 controllers look incomplete (informational only)
+  ansible.builtin.debug:
+    msg: >-
+      cgroup.controllers reports: {{ cgroup_controllers.stdout | default('unreadable') }}.
+      Expect at least cpu, memory, pids, io for reliable nested k3s — verify manually if any
+      are missing (see docs/PRODUCTION_VALIDATION_CHECKLIST.md "Lab boot" section).
+  when: cgroup_controllers.rc == 0
+
+- name: Create data/config directories
+  ansible.builtin.file:
+    path: "{{ item }}"
+    state: directory
+    owner: root
+    group: docker
+    mode: "0750"
+  loop:
+    - /opt/rootnode/lab-host
+    - "{{ rootnode_data_root }}/lab-work"   # disposable — see docs/BACKUP_DR.md, never backed up
+
+- name: Render production docker-compose.yml
+  ansible.builtin.template:
+    src: "{{ role_path }}/../../../docker/lab-host/docker-compose.production.yml"
+    dest: /opt/rootnode/lab-host/docker-compose.yml
+    owner: root
+    group: root
+    mode: "0640"
+  notify: restart rootnode-lab-host
+
+- name: Deploy systemd unit
+  ansible.builtin.template:
+    src: rootnode-lab-host.service.j2
+    dest: /etc/systemd/system/rootnode-lab-host.service
+    mode: "0644"
+  notify: restart rootnode-lab-host
+
+- name: Enable and start rootnode-lab-host
+  ansible.builtin.systemd:
+    name: rootnode-lab-host
+    enabled: true
+    state: started
+    daemon_reload: true
+
+# Storage-driver/networking daemon options live in the docker-tls role's daemon.json.j2 —
+# Docker only ever reads ONE /etc/docker/daemon.json, so that's the single source of truth for
+# this host's whole daemon config, not just its TLS settings (see that role's template).

infra/ansible/roles/lab-host/templates/rootnode-lab-host.service.j2

@@ -0,0 +1,17 @@
+[Unit]
+Description=RootNode Academy Lab Host services (egress proxy + monitoring agents)
+Requires=docker.service
+After=docker.service network-online.target
+Wants=network-online.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+WorkingDirectory=/opt/rootnode/lab-host
+ExecStart=/usr/bin/docker compose -f docker-compose.yml up -d --remove-orphans
+ExecStop=/usr/bin/docker compose -f docker-compose.yml down
+ExecReload=/usr/bin/docker compose -f docker-compose.yml up -d --remove-orphans
+TimeoutStartSec=180
+
+[Install]
+WantedBy=multi-user.target

infra/ansible/roles/monitoring-agent/handlers/main.yml

@@ -0,0 +1,16 @@
+---
+- name: reload prometheus
+  ansible.builtin.command: docker compose -f /opt/rootnode/platform/docker-compose.yml restart prometheus
+  changed_when: true
+
+- name: reload alertmanager
+  ansible.builtin.command: docker compose -f /opt/rootnode/platform/docker-compose.yml restart alertmanager
+  changed_when: true
+
+- name: restart platform promtail
+  ansible.builtin.command: docker compose -f /opt/rootnode/platform/docker-compose.yml restart promtail
+  changed_when: true
+
+- name: restart lab-host promtail
+  ansible.builtin.command: docker compose -f /opt/rootnode/lab-host/docker-compose.yml restart promtail
+  changed_when: true

infra/ansible/roles/monitoring-agent/tasks/main.yml

@@ -0,0 +1,75 @@
+---
+# Deploys infra/monitoring/ configs to whichever host needs them. Named monitoring-agent for
+# historical reasons in this repo's role list, but it deploys both the "agent" pieces
+# (node-exporter/cadvisor/promtail configs, already referenced directly by the platform/
+# lab-host compose files) and the central stack's config (Prometheus/Alertmanager/Loki/Grafana
+# on rn-platform-01 only).
+
+- name: Create /opt/rootnode/monitoring (rn-platform-01)
+  ansible.builtin.file:
+    path: /opt/rootnode/monitoring/rules
+    state: directory
+    mode: "0755"
+  when: inventory_hostname in groups['platform']
+
+- name: Deploy Prometheus config
+  ansible.builtin.template:
+    src: "{{ role_path }}/../../../monitoring/prometheus/prometheus.yml.j2"
+    dest: /opt/rootnode/monitoring/prometheus.yml
+    mode: "0644"
+  when: inventory_hostname in groups['platform']
+  notify: reload prometheus
+
+- name: Deploy alert rules
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../monitoring/prometheus/rules/rootnode.yml"
+    dest: /opt/rootnode/monitoring/rules/rootnode.yml
+    mode: "0644"
+  when: inventory_hostname in groups['platform']
+  notify: reload prometheus
+
+- name: Deploy blackbox_exporter config
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../monitoring/prometheus/blackbox.yml"
+    dest: /opt/rootnode/monitoring/blackbox.yml
+    mode: "0644"
+  when: inventory_hostname in groups['platform']
+
+- name: Deploy Alertmanager config
+  ansible.builtin.template:
+    src: "{{ role_path }}/../../../monitoring/alertmanager/alertmanager.yml.j2"
+    dest: /opt/rootnode/monitoring/alertmanager.yml
+    mode: "0644"
+  when: inventory_hostname in groups['platform']
+  notify: reload alertmanager
+
+- name: Deploy Loki config
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../monitoring/loki/loki-config.yml"
+    dest: /opt/rootnode/monitoring/loki-config.yml
+    mode: "0644"
+  when: inventory_hostname in groups['platform']
+
+- name: Deploy Grafana provisioning + dashboards
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../monitoring/grafana/{{ item }}/"
+    dest: "/opt/rootnode/monitoring/grafana/{{ item }}/"
+    mode: "0644"
+  loop: [provisioning, dashboards]
+  when: inventory_hostname in groups['platform']
+
+- name: Deploy platform-side promtail config
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../monitoring/promtail/promtail-config.platform.yml"
+    dest: /opt/rootnode/monitoring/promtail-config.yml
+    mode: "0644"
+  when: inventory_hostname in groups['platform']
+  notify: restart platform promtail
+
+- name: Deploy lab-host promtail config
+  ansible.builtin.template:
+    src: "{{ role_path }}/../../../monitoring/promtail/promtail-config.lab-host.yml.j2"
+    dest: /opt/rootnode/lab-host/promtail-config.yml
+    mode: "0644"
+  when: inventory_hostname in groups['lab_host']
+  notify: restart lab-host promtail

infra/ansible/roles/platform/handlers/main.yml

@@ -0,0 +1,6 @@
+---
+- name: restart rootnode-platform
+  ansible.builtin.systemd:
+    name: rootnode-platform
+    state: restarted
+    daemon_reload: true

infra/ansible/roles/platform/tasks/main.yml

@@ -0,0 +1,85 @@
+---
+# rn-platform-01: Docker Engine, directory structure, rendered compose file + env files,
+# Postgres tuning overlay, reverse proxy config, and the systemd unit that runs it all.
+# Docker TLS material and the host firewall are separate roles (docker-tls, firewall) run
+# before this one in site.yml — this role assumes both are already in place.
+
+- name: Install Docker Engine
+  ansible.builtin.import_tasks: "{{ role_path }}/../common/tasks/docker-engine.yml"
+
+- name: Create data/config directories
+  ansible.builtin.file:
+    path: "{{ item }}"
+    state: directory
+    owner: root
+    group: docker
+    mode: "0750"
+  loop:
+    - "{{ rootnode_data_root }}/postgres"
+    - "{{ rootnode_data_root }}/backups"
+    - /opt/rootnode/platform
+    - /opt/rootnode/platform/postgresql.conf.d
+    - /etc/rootnode/provisioner-config
+
+- name: Deploy Postgres tuning overlay
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../docker/postgres/postgresql.conf.d/00-rootnode-baseline.conf"
+    dest: /opt/rootnode/platform/postgresql.conf.d/00-rootnode-baseline.conf
+    mode: "0644"
+  notify: restart rootnode-platform
+
+- name: Deploy provisioner-config overlay ({{ env }})
+  ansible.builtin.copy:
+    src: "{{ role_path }}/../../../../environments/{{ env }}/provisioner-config/"
+    dest: /etc/rootnode/provisioner-config/
+    mode: "0644"
+  notify: restart rootnode-platform
+
+- name: Deploy per-service env files (from Ansible Vault-backed variables — see group_vars)
+  ansible.builtin.template:
+    src: "{{ item }}.env.j2"
+    dest: "/etc/rootnode/{{ item }}.env"
+    owner: root
+    group: root
+    mode: "0600"
+  loop:
+    - platform
+    - provisioner
+    - gateway
+    - postgres
+  notify: restart rootnode-platform
+
+- name: Render production docker-compose.yml
+  ansible.builtin.template:
+    src: "{{ role_path }}/../../../docker/platform/docker-compose.production.yml"
+    dest: /opt/rootnode/platform/docker-compose.yml
+    owner: root
+    group: root
+    mode: "0640"
+  notify: restart rootnode-platform
+
+- name: Render Caddyfile
+  ansible.builtin.template:
+    src: "{{ role_path }}/../../../docker/platform/Caddyfile.j2"
+    dest: /opt/rootnode/platform/Caddyfile
+    owner: root
+    group: root
+    mode: "0644"
+  notify: restart rootnode-platform
+
+- name: Deploy systemd unit
+  ansible.builtin.template:
+    src: rootnode-platform.service.j2
+    dest: /etc/systemd/system/rootnode-platform.service
+    mode: "0644"
+  notify: restart rootnode-platform
+
+# The `backup` role (applied after this one in site.yml) deploys the backup script and cron —
+# kept separate since it also has to run correctly on a host that ISN'T freshly deployed.
+
+- name: Enable and start rootnode-platform
+  ansible.builtin.systemd:
+    name: rootnode-platform
+    enabled: true
+    state: started
+    daemon_reload: true

infra/ansible/roles/platform/templates/gateway.env.j2

@@ -0,0 +1,13 @@
+# Rendered by Ansible — see platform.env.j2 for the pattern.
+PLATFORM_API_URL=http://api:4300
+PROVISIONER_URL=http://provisioner:4100
+PROVISIONER_SHARED_SECRET={{ vault_provisioner_shared_secret }}
+GATEWAY_PORT=4200
+# Phase 4.1 — mTLS client identity for the Lab Host Router (data plane). Only used when a
+# lab_host's routing_mode is 'router' (see platform/gateway/src/lab-endpoint.js); harmless if
+# every configured lab_host is still 'direct'. Paths are inside the container — mounted from
+# /etc/rootnode/lab-router-tls on the host by the `docker-tls` role, same pattern as the
+# Provisioner's Docker TLS client cert.
+LAB_ROUTER_TLS_CA=/tls/ca.pem
+LAB_ROUTER_TLS_CERT=/tls/gateway-client-cert.pem
+LAB_ROUTER_TLS_KEY=/tls/gateway-client-key.pem

infra/ansible/roles/platform/templates/platform.env.j2

@@ -0,0 +1,24 @@
+# Rendered by Ansible from infra/environments/{{ env }}/platform.env.template's shape —
+# real values come from group_vars/{{ env }}.yml + the encrypted vault file. Do not hand-edit
+# on the host; re-run the platform role instead.
+
+# service names, not localhost — production runs these on a named Docker bridge network
+# (rn-platform-internal), not network_mode: host like the dev compose file does.
+PLATFORM_DB_URL=postgres://rootnode_platform:{{ vault_postgres_password }}@postgres:5432/rootnode_platform
+PROVISIONER_URL=http://provisioner:4100
+PROVISIONER_SHARED_SECRET={{ vault_provisioner_shared_secret }}
+PLATFORM_API_PORT=4300
+
+STUDENT_SESSION_TTL_HOURS=8
+STUDENT_SESSION_IDLE_HOURS=2
+INSTRUCTOR_SESSION_TTL_HOURS=12
+INSTRUCTOR_SESSION_IDLE_HOURS=2
+
+COOKIE_SECURE=1
+TRUST_PROXY=1
+
+# Phase 4.1 §17 — instructor "needs attention" thresholds. Commented out (code defaults apply:
+# 3 failures, 7 stale days) — uncomment and override in group_vars/{{ env }}.yml only if a
+# cohort's real usage shows the defaults are wrong for it.
+# NEEDS_ATTENTION_FAIL_THRESHOLD=3
+# NEEDS_ATTENTION_STALE_DAYS=7

infra/ansible/roles/platform/templates/postgres.env.j2

@@ -0,0 +1,4 @@
+# Rendered by Ansible — see platform.env.j2 for the pattern.
+POSTGRES_USER=rootnode_platform
+POSTGRES_PASSWORD={{ vault_postgres_password }}
+POSTGRES_DB=rootnode_platform

infra/ansible/roles/platform/templates/provisioner.env.j2

@@ -0,0 +1,11 @@
+# Rendered by Ansible — see platform.env.j2 for the pattern.
+PLATFORM_DB_URL=postgres://rootnode_platform:{{ vault_postgres_password }}@postgres:5432/rootnode_platform
+PROVISIONER_SHARED_SECRET={{ vault_provisioner_shared_secret }}
+PROVISIONER_PORT=4100
+PROVISIONER_CONFIG_DIR=/app/config
+
+LAB_IMAGE_REF={{ registry }}/rootnode/lab:{{ image_tag }}
+
+EGRESS_PROXY_PORT=3128
+DNS_RESOLVER=127.0.0.11
+NO_PROXY_CIDRS=10.42.0.0/16,10.43.0.0/16

infra/ansible/roles/platform/templates/rootnode-platform.service.j2

@@ -0,0 +1,17 @@
+[Unit]
+Description=RootNode Academy Platform (docker compose)
+Requires=docker.service
+After=docker.service network-online.target
+Wants=network-online.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+WorkingDirectory=/opt/rootnode/platform
+ExecStart=/usr/bin/docker compose -f docker-compose.yml up -d --remove-orphans
+ExecStop=/usr/bin/docker compose -f docker-compose.yml down
+ExecReload=/usr/bin/docker compose -f docker-compose.yml up -d --remove-orphans
+TimeoutStartSec=300
+
+[Install]
+WantedBy=multi-user.target

infra/ansible/site.yml

@@ -0,0 +1,52 @@
+---
+# Top-level playbook — full production/staging deployment. Idempotent: re-running against an
+# already-deployed host converges it, doesn't rebuild from scratch (Phase 4 §20 requirement).
+#
+# Usage:
+#   ansible-playbook site.yml -i inventory/production.ini --vault-password-file .vault_pass
+#   ansible-playbook site.yml -i inventory/staging.ini -e env=staging
+#
+# Role order matters: firewall and docker-tls must land before platform/lab-host bring up
+# services that depend on the network policy / TLS material already being in place.
+
+- name: Base hardening — all RootNode hosts
+  hosts: rootnode
+  become: true
+  roles:
+    - common
+
+- name: Firewall policy — all RootNode hosts
+  hosts: rootnode
+  become: true
+  roles:
+    - firewall
+
+- name: Docker TLS — both hosts (server cert on lab_host, client cert on platform)
+  hosts: rootnode
+  become: true
+  roles:
+    - docker-tls
+
+- name: Deploy the Platform VM
+  hosts: platform
+  become: true
+  roles:
+    - platform
+
+- name: Deploy the Lab Host VM
+  hosts: lab_host
+  become: true
+  roles:
+    - lab-host
+
+- name: Deploy monitoring configuration — both hosts
+  hosts: rootnode
+  become: true
+  roles:
+    - monitoring-agent
+
+- name: Deploy backup automation — Platform VM only (that's where Postgres lives)
+  hosts: platform
+  become: true
+  roles:
+    - backup

infra/backup/backup-postgres.sh

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+# Postgres backup — Tier 1 (irreplaceable) data per docs/BACKUP_DR.md. Runs via cron on
+# rn-platform-01 (deployed by the `backup` Ansible role), and locally testable against ANY
+# reachable Postgres (that's exactly what infra/backup/test-backup-restore.sh does).
+#
+# Produces one gzip-compressed pg_dump per run, encrypts it, prunes local copies past
+# BACKUP_RETENTION_DAYS, and (if BACKUP_OFFSITE_TARGET is set) rsyncs the encrypted copy
+# off-host. Writes a Prometheus textfile-collector metric so infra/monitoring/'s BackupFailed/
+# BackupAging alerts have real data to fire on.
+#
+# Required env: PLATFORM_DB_URL, BACKUP_DIR, BACKUP_ENCRYPTION_PASSPHRASE
+# Optional env: BACKUP_RETENTION_DAYS (default 30), BACKUP_OFFSITE_TARGET, METRICS_TEXTFILE_DIR
+set -euo pipefail
+
+: "${PLATFORM_DB_URL:?PLATFORM_DB_URL is required}"
+: "${BACKUP_DIR:?BACKUP_DIR is required}"
+: "${BACKUP_ENCRYPTION_PASSPHRASE:?BACKUP_ENCRYPTION_PASSPHRASE is required — see docs/BACKUP_DR.md}"
+BACKUP_RETENTION_DAYS="${BACKUP_RETENTION_DAYS:-30}"
+METRICS_TEXTFILE_DIR="${METRICS_TEXTFILE_DIR:-}"
+
+TS="$(date -u +%Y%m%dT%H%M%SZ)"
+mkdir -p "$BACKUP_DIR"
+DUMP_FILE="$BACKUP_DIR/rootnode-platform-$TS.sql.gz"
+ENC_FILE="$DUMP_FILE.gpg"
+
+write_metric() {
+  # $1 = metric line. Written atomically (tmp+rename) so Prometheus's node-exporter
+  # textfile-collector never scrapes a half-written file.
+  [ -n "$METRICS_TEXTFILE_DIR" ] || return 0
+  mkdir -p "$METRICS_TEXTFILE_DIR"
+  local tmp; tmp="$(mktemp "$METRICS_TEXTFILE_DIR/.rootnode_backup.XXXXXX")"
+  echo "$1" > "$tmp"
+  mv -f "$tmp" "$METRICS_TEXTFILE_DIR/rootnode_backup.prom"
+}
+
+fail() {
+  echo "BACKUP FAILED: $1" >&2
+  write_metric "rootnode_backup_last_run_success 0"
+  exit 1
+}
+trap 'fail "unexpected error at line $LINENO"' ERR
+
+echo "==> Dumping $PLATFORM_DB_URL to $DUMP_FILE"
+pg_dump --format=plain --no-owner --no-privileges "$PLATFORM_DB_URL" | gzip -9 > "$DUMP_FILE"
+
+# Fail loudly on a suspiciously small dump (empty/truncated) rather than "successfully"
+# backing up nothing — a real, if crude, sanity check.
+DUMP_SIZE=$(stat -c%s "$DUMP_FILE" 2>/dev/null || stat -f%z "$DUMP_FILE")
+[ "$DUMP_SIZE" -gt 1024 ] || fail "dump is suspiciously small ($DUMP_SIZE bytes) — refusing to treat this as a real backup"
+
+echo "==> Encrypting (AES-256, symmetric passphrase — see docs/BACKUP_DR.md for the recovery-key handling policy)"
+gpg --batch --yes --passphrase "$BACKUP_ENCRYPTION_PASSPHRASE" --symmetric --cipher-algo AES256 \
+  --output "$ENC_FILE" "$DUMP_FILE"
+rm -f "$DUMP_FILE"   # never leave the plaintext dump on disk once the encrypted copy exists
+
+echo "==> Local backup complete: $ENC_FILE ($(stat -c%s "$ENC_FILE" 2>/dev/null || stat -f%z "$ENC_FILE") bytes)"
+
+if [ -n "${BACKUP_OFFSITE_TARGET:-}" ]; then
+  echo "==> Copying off-host to $BACKUP_OFFSITE_TARGET"
+  # rsync over SSH works for both a Hetzner Storage Box (SSH/SFTP-native) and any other
+  # SSH-reachable target — the adapter point the Phase 4 spec asked for is this one variable,
+  # not a vendor-specific script. An S3-compatible target uses `aws s3 cp` / `rclone` instead;
+  # see docs/BACKUP_DR.md for both forms.
+  rsync -az --timeout=120 "$ENC_FILE" "$BACKUP_OFFSITE_TARGET/" \
+    || fail "off-host copy to $BACKUP_OFFSITE_TARGET failed"
+else
+  echo "==> BACKUP_OFFSITE_TARGET not set — local-only backup (fine for a local test run, NOT fine for production, see docs/BACKUP_DR.md)"
+fi
+
+echo "==> Pruning local backups older than $BACKUP_RETENTION_DAYS days"
+find "$BACKUP_DIR" -name 'rootnode-platform-*.sql.gz.gpg' -mtime "+$BACKUP_RETENTION_DAYS" -delete
+
+write_metric "rootnode_backup_last_run_success 1
+rootnode_backup_last_success_timestamp_seconds $(date +%s)
+rootnode_backup_size_bytes $(stat -c%s "$ENC_FILE" 2>/dev/null || stat -f%z "$ENC_FILE")"
+
+echo "==> Backup succeeded"

infra/backup/restore-postgres.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+# Restores an encrypted backup produced by backup-postgres.sh into a target database.
+# Deliberately requires an EXPLICIT target — never silently restores over the live production
+# database ("what would you do if this ran the wrong way" is a real disaster-recovery failure
+# mode, so making that impossible to trigger by accident matters more than convenience here).
+#
+# Usage: ./restore-postgres.sh <encrypted-backup-file> <target-db-url>
+#
+# For a REAL production restore, target-db-url should point at a FRESH database created for
+# this purpose (docs/RUNBOOK_POSTGRES_RESTORE.md walks through creating it) — restoring into a
+# database that already has data merges/conflicts rather than cleanly replacing it.
+set -euo pipefail
+
+ENC_FILE="${1:?usage: restore-postgres.sh <encrypted-backup-file> <target-db-url>}"
+TARGET_DB_URL="${2:?usage: restore-postgres.sh <encrypted-backup-file> <target-db-url>}"
+: "${BACKUP_ENCRYPTION_PASSPHRASE:?BACKUP_ENCRYPTION_PASSPHRASE is required to decrypt}"
+
+[ -f "$ENC_FILE" ] || { echo "No such file: $ENC_FILE" >&2; exit 1; }
+
+TMPDIR="$(mktemp -d)"
+trap 'rm -rf "$TMPDIR"' EXIT
+DUMP_FILE="$TMPDIR/restore.sql.gz"
+
+echo "==> Decrypting $ENC_FILE"
+gpg --batch --yes --passphrase "$BACKUP_ENCRYPTION_PASSPHRASE" --decrypt --output "$DUMP_FILE" "$ENC_FILE"
+
+echo "==> Confirming target is reachable"
+psql "$TARGET_DB_URL" -c "SELECT 1" > /dev/null
+
+echo "==> Target database currently has these tables (should be empty/unimportant before you continue):"
+psql "$TARGET_DB_URL" -c "\dt" || true
+read -r -p "Type RESTORE to proceed against $TARGET_DB_URL: " CONFIRM
+[ "$CONFIRM" = "RESTORE" ] || { echo "Aborted."; exit 1; }
+
+echo "==> Restoring"
+gunzip -c "$DUMP_FILE" | psql "$TARGET_DB_URL"
+
+echo "==> Restore complete. Verify with infra/backup/verify-restore.sh $TARGET_DB_URL"

infra/backup/seed-realistic-data.js

@@ -0,0 +1,94 @@
+#!/usr/bin/env node
+// Seeds realistic academy data for the Phase 4.1 §20 destructive restore drill — an owner, an
+// admin instructor, a cohort, 3 students, progress, attempts, an assessment definition +
+// session, and an achievement. Uses the REAL Platform API over HTTP for everything that
+// doesn't need a live Provisioner/k3s Lab (owner login, instructor/cohort/student/assessment
+// creation — genuinely exercises the real RBAC/creation code paths), and direct SQL inserts
+// only for progress/attempts/achievements (those need real scenario activity in the full app;
+// re-running the whole learning engine here would just re-prove what e2e-phase3b.js already
+// proves — this drill is about DATA DURABILITY, not re-testing scenario validation).
+//
+// Usage: PLATFORM_API_URL=http://localhost:PORT PLATFORM_DB_URL=postgres://... node seed-realistic-data.js
+
+const { Pool } = require('../../platform/api/node_modules/pg');
+
+const API = process.env.PLATFORM_API_URL || 'http://localhost:4390';
+const DB_URL = process.env.PLATFORM_DB_URL;
+if (!DB_URL) { console.error('Set PLATFORM_DB_URL'); process.exit(1); }
+
+function makeSession() {
+  const jar = new Map();
+  function cookieHeader() { return [...jar].map(([k, v]) => `${k}=${v}`).join('; '); }
+  function absorb(res) {
+    const cookies = typeof res.headers.getSetCookie === 'function' ? res.headers.getSetCookie() : [];
+    for (const c of cookies) {
+      const [pair] = c.split(';');
+      const eq = pair.indexOf('=');
+      if (eq === -1) continue;
+      jar.set(pair.slice(0, eq).trim(), pair.slice(eq + 1).trim());
+    }
+  }
+  return {
+    async req(method, path, body) {
+      const headers = { 'Content-Type': 'application/json' };
+      if (cookieHeader()) headers.Cookie = cookieHeader();
+      if (!['GET', 'HEAD'].includes(method)) headers['X-CSRF-Token'] = jar.get('rn_csrf_i') || '';
+      const res = await fetch(`${API}${path}`, { method, headers, body: body ? JSON.stringify(body) : undefined });
+      absorb(res);
+      const text = await res.text();
+      let json; try { json = JSON.parse(text); } catch { json = text; }
+      if (!res.ok) throw new Error(`${method} ${path} -> ${res.status}: ${JSON.stringify(json)}`);
+      return json;
+    },
+  };
+}
+
+async function main() {
+  const owner = makeSession();
+  await owner.req('POST', '/api/auth/instructor/login', { email: '[email protected]', password: 'DrillOwnerPass!2026' });
+  console.log('  owner login ok');
+
+  const admin = await owner.req('POST', '/api/admin/instructors', {
+    email: '[email protected]', display_name: 'Drill Admin', password: 'DrillAdminPass!2026', role: 'admin',
+  });
+  console.log('  admin instructor created:', admin.instructor_id);
+
+  const cohort = await owner.req('POST', '/api/admin/cohorts', { cohort_id: 'drill-cohort-01', name: 'Restore Drill Cohort' });
+  console.log('  cohort created');
+
+  const students = [];
+  for (const name of ['Drill Alice', 'Drill Bob', 'Drill Carlos']) {
+    const s = await owner.req('POST', '/api/admin/students', { display_name: name, cohort_id: 'drill-cohort-01' });
+    students.push(s.student_id);
+  }
+  console.log('  3 students rostered and enrolled:', students.join(', '));
+
+  const assessment = await owner.req('POST', '/api/admin/assessments', {
+    id: 'drill-exam-01', type: 'exam', title: 'Restore Drill Exam', duration_minutes: 30, hint_policy: 'disabled',
+    pool_spec: { required: ['pod-basics-mcq'], random: [] },
+  });
+  console.log('  assessment definition created:', assessment.assessment_definition_id || 'drill-exam-01');
+
+  // Direct SQL for progress/attempts/achievements — see file header for why.
+  const pool = new Pool({ connectionString: DB_URL });
+  for (const studentId of students) {
+    // environment_id is a real FK to the Provisioner's environments table (nullable) — left
+    // NULL here rather than faking a row that doesn't exist, same as how a genuinely old
+    // attempt whose environment has long since been cleaned up would look in real data.
+    await pool.query(
+      `INSERT INTO scenario_attempts (student_id, scenario_id, status, result, started_at, completed_at, validation_attempt_count, validation_pass_count)
+       VALUES ($1, 'pod-basics-mcq', 'completed', 'passed', now() - interval '1 hour', now(), 1, 1)`,
+      [studentId]
+    );
+    await pool.query(
+      `INSERT INTO achievements (student_id, achievement_type, stage_id, achieved_at) VALUES ($1, 'stage_completed', 'foundation', now())`,
+      [studentId]
+    );
+  }
+  await pool.end();
+  console.log('  progress/attempts/achievements seeded for all 3 students');
+
+  console.log('\nSeed complete.');
+}
+
+main().catch((e) => { console.error('SEED FAILED:', e.message); process.exit(1); });

infra/backup/test-backup-restore.sh

@@ -0,0 +1,133 @@
+#!/usr/bin/env bash
+# Local test (Phase 4 §29): a REAL end-to-end backup/restore cycle against disposable local
+# Postgres containers — not a mock. Applies the actual Platform API migration runner (the same
+# code path production uses, platform/api/src/db.js) so the schema under test is genuinely the
+# real one, inserts sample data, backs it up, restores into a SECOND empty Postgres, and
+# verifies the result. Proves the backup/restore MECHANISM works; does NOT prove anything about
+# the real off-host target (Storage Box/S3) — that needs real credentials, marked as
+# hardware/credential-dependent below.
+set -euo pipefail
+cd "$(dirname "$0")/../.."   # repo root
+
+SRC_CONTAINER=rootnode-backup-test-src
+DST_CONTAINER=rootnode-backup-test-dst
+SRC_PORT=55432
+DST_PORT=55433
+TESTDIR="$(mktemp -d)"
+export BACKUP_ENCRYPTION_PASSPHRASE="test-passphrase-not-for-production"
+
+cleanup() {
+  docker rm -f "$SRC_CONTAINER" "$DST_CONTAINER" >/dev/null 2>&1 || true
+  rm -rf "$TESTDIR"
+}
+trap cleanup EXIT
+
+# backup-postgres.sh/restore-postgres.sh assume real postgresql-client + gpg binaries — true on
+# a real deployment host (the `backup` Ansible role installs postgresql-client there). This dev
+# machine may not have psql/pg_dump installed at all, so for THIS TEST ONLY we shim them as
+# thin wrappers around `docker exec` into the two disposable test containers — the scripts
+# under test are otherwise completely unmodified from what production actually runs.
+if ! command -v psql >/dev/null 2>&1 || ! command -v pg_dump >/dev/null 2>&1; then
+  echo "==> psql/pg_dump not found locally — shimming both via docker exec for this test run"
+  SHIM_BIN="$TESTDIR/bin"
+  mkdir -p "$SHIM_BIN"
+  # Both wrappers pick a container from the target port (explicit -p, or embedded in a
+  # postgres://...:PORT/... URL), then re-exec psql/pg_dump INSIDE that container against ITS
+  # OWN localhost:5432 — the host-side port mapping (55432/55433) doesn't exist inside the
+  # container's network namespace, so the connection target itself must be replaced, not just
+  # which container runs the command.
+  cat > "$SHIM_BIN/psql" <<'EOF'
+#!/usr/bin/env bash
+args=(); port=""; want_port=0; skip_next=0
+for a in "$@"; do
+  if [ "$skip_next" = "1" ]; then
+    [ "$want_port" = "1" ] && port="$a"
+    skip_next=0; want_port=0; continue
+  fi
+  if [ "$a" = "-p" ]; then skip_next=1; want_port=1; continue; fi
+  if [ "$a" = "-h" ]; then skip_next=1; want_port=0; continue; fi
+  if [[ "$a" =~ ^postgres://[^:]+:[^@]+@[^:]+:([0-9]+)/ ]]; then
+    port="${BASH_REMATCH[1]}"
+    continue   # drop the URL — reconnect locally inside the container instead
+  fi
+  args+=("$a")
+done
+case "$port" in
+  55433) c="rootnode-backup-test-dst" ;;
+  *) c="rootnode-backup-test-src" ;;
+esac
+# Only forward local stdin (-i) for the one call that actually reads SQL from it (no -c/-tAc
+# in its args, i.e. `psql <target>` fed by a pipe) — every -c/-tAc call is self-contained and
+# must NOT hold docker exec's stdin open, or it silently steals bytes meant for a later `read`
+# elsewhere in the calling script (exactly what broke restore-postgres.sh's confirmation prompt
+# the first time this shim was written).
+needs_stdin=1
+for a in "${args[@]}"; do [ "$a" = "-c" ] || [ "$a" = "-tAc" ] && needs_stdin=0; done
+if [ "$needs_stdin" = "1" ]; then
+  exec docker exec -e PGPASSWORD=postgres -i "$c" psql -h localhost -U postgres "${args[@]}"
+else
+  exec docker exec -e PGPASSWORD=postgres "$c" psql -h localhost -U postgres "${args[@]}"
+fi
+EOF
+  cat > "$SHIM_BIN/pg_dump" <<'EOF'
+#!/usr/bin/env bash
+args=()
+for a in "$@"; do
+  if [[ "$a" =~ ^postgres:// ]]; then continue; fi   # source is always the src container here
+  args+=("$a")
+done
+exec docker exec -e PGPASSWORD=postgres -i rootnode-backup-test-src pg_dump -h localhost -U postgres "${args[@]}"
+EOF
+  chmod +x "$SHIM_BIN/psql" "$SHIM_BIN/pg_dump"
+  export PATH="$SHIM_BIN:$PATH"
+fi
+
+echo "==> Starting source Postgres (the one we'll back up)"
+docker run -d --name "$SRC_CONTAINER" -e POSTGRES_PASSWORD=postgres -p "$SRC_PORT:5432" postgres:16-alpine >/dev/null
+echo "==> Starting destination Postgres (the one we'll restore into)"
+docker run -d --name "$DST_CONTAINER" -e POSTGRES_PASSWORD=postgres -p "$DST_PORT:5432" postgres:16-alpine >/dev/null
+
+echo "==> Waiting for both to accept connections"
+for port in "$SRC_PORT" "$DST_PORT"; do
+  for i in $(seq 1 30); do
+    PGPASSWORD=postgres psql -h localhost -p "$port" -U postgres -c "SELECT 1" >/dev/null 2>&1 && break
+    sleep 1
+  done
+done
+
+SRC_DB_URL="postgres://postgres:postgres@localhost:$SRC_PORT/postgres"
+DST_DB_URL="postgres://postgres:postgres@localhost:$DST_PORT/postgres"
+
+echo "==> Applying the REAL Provisioner migrations first (Platform API's scenario_attempts has a real FK to Provisioner's environments table — documented cross-service ordering dependency, see docs/PHASE2B_ADMIN_AND_PLATFORM_DATA.md)"
+( cd platform/provisioner && [ -d node_modules ] || npm install --no-audit --no-fund >/dev/null
+  PLATFORM_DB_URL="$SRC_DB_URL" node -e "require('./src/db').runMigrations().then((m)=>console.log('Applied:', m.join(', ')))" )
+
+echo "==> Applying the REAL Platform API migrations against the source"
+( cd platform/api && [ -d node_modules ] || npm install --no-audit --no-fund >/dev/null
+  PLATFORM_DB_URL="$SRC_DB_URL" node -e "require('./src/db').runMigrations().then((m)=>console.log('Applied:', m.join(', ')))" )
+
+echo "==> Inserting sample data (a student, so the backup has something real to carry)"
+PGPASSWORD=postgres psql -h localhost -p "$SRC_PORT" -U postgres -c \
+  "INSERT INTO students (student_id, display_name) VALUES ('student-backup-test', 'Backup Test Student');"
+
+echo "==> Running backup-postgres.sh against the source"
+BACKUP_DIR="$TESTDIR/backups" PLATFORM_DB_URL="$SRC_DB_URL" ./infra/backup/backup-postgres.sh
+
+ENC_FILE=$(ls "$TESTDIR"/backups/*.sql.gz.gpg | head -1)
+[ -f "$ENC_FILE" ] || { echo "FAIL: no encrypted backup file produced"; exit 1; }
+echo "==> Backup produced: $ENC_FILE"
+
+echo "==> Restoring into the destination (non-interactive: piping the confirmation)"
+echo "RESTORE" | BACKUP_ENCRYPTION_PASSPHRASE="$BACKUP_ENCRYPTION_PASSPHRASE" ./infra/backup/restore-postgres.sh "$ENC_FILE" "$DST_DB_URL"
+
+echo "==> Verifying the restore"
+./infra/backup/verify-restore.sh "$DST_DB_URL"
+
+echo "==> Confirming the sample student actually round-tripped"
+RESTORED_NAME=$(PGPASSWORD=postgres psql -h localhost -p "$DST_PORT" -U postgres -tAc \
+  "SELECT display_name FROM students WHERE student_id = 'student-backup-test'")
+[ "$RESTORED_NAME" = "Backup Test Student" ] || { echo "FAIL: restored student data doesn't match"; exit 1; }
+
+echo
+echo "OK: full backup -> encrypt -> restore -> verify cycle succeeded against real local Postgres."
+echo "NOT TESTED HERE (needs real credentials/hardware): off-host copy to a real Storage Box/S3 target."

infra/backup/test-destructive-restore-drill.sh

@@ -0,0 +1,149 @@
+#!/usr/bin/env bash
+# Phase 4.1 §20 — the DESTRUCTIVE disaster-recovery drill, one level up from
+# test-backup-restore.sh's mechanism-only test: seeds realistic academy data through the REAL
+# Platform API (owner, admin instructor, cohort, 3 students, progress, attempts, an assessment
+# definition, achievements), backs it up, DESTROYS the disposable Postgres storage entirely
+# (docker rm — not just "restore into a second container," the actual source is gone),
+# recreates Postgres from nothing, restores, and boots the REAL Platform API again against the
+# restored database to prove the whole stack — not just the SQL — comes back.
+#
+# Never touches the developer's real persistent database — every Postgres here is a disposable
+# container on a throwaway port, created and destroyed entirely within this script.
+set -euo pipefail
+cd "$(dirname "$0")/../.."   # repo root
+
+CONTAINER=rootnode-drill-postgres
+PORT=55434
+API_PORT=4390
+TESTDIR="$(mktemp -d)"
+# curriculum.js defaults to platform/api/scenarios/{data,bundles} — only present inside the
+# Docker image build (COPY scenarios/ ./scenarios/). Running src/server.js directly from
+# source (as this drill does, to avoid needing a full container build) needs these pointed at
+# the repo's real scenario content instead.
+export SCENARIOS_DIR="$PWD/scenarios/data"
+export BUNDLES_DIR="$PWD/scenarios/bundles"
+export CURRICULUM_PATH_FILE="$PWD/scenarios/rootnode-path.json"
+export BACKUP_ENCRYPTION_PASSPHRASE="drill-passphrase-not-for-production"
+export PROVISIONER_SHARED_SECRET="drill-shared-secret-not-for-production"
+
+API_PID=""
+cleanup() {
+  [ -n "$API_PID" ] && kill "$API_PID" 2>/dev/null || true
+  docker rm -f "$CONTAINER" >/dev/null 2>&1 || true
+  rm -rf "$TESTDIR"
+}
+trap cleanup EXIT
+
+if ! command -v psql >/dev/null 2>&1 || ! command -v pg_dump >/dev/null 2>&1; then
+  echo "==> psql/pg_dump not found locally — reusing the same docker-exec shim as test-backup-restore.sh"
+  SHIM_BIN="$TESTDIR/bin"; mkdir -p "$SHIM_BIN"
+  # Same shim as test-backup-restore.sh (see that file's comment for the full "why") — the URL
+  # is DROPPED, not kept, since the host-side port it names doesn't exist inside the
+  # container's own network namespace; -tAc counts as a self-contained call (needs no stdin)
+  # the same way -c does, or the admin-verification queries below would hang waiting on stdin.
+  cat > "$SHIM_BIN/psql" <<'EOF'
+#!/usr/bin/env bash
+args=(); skip_next=0
+for a in "$@"; do
+  if [ "$skip_next" = "1" ]; then skip_next=0; continue; fi
+  if [ "$a" = "-p" ] || [ "$a" = "-h" ]; then skip_next=1; continue; fi
+  if [[ "$a" =~ ^postgres://[^:]+:[^@]+@[^:]+:([0-9]+)/ ]]; then continue; fi   # drop the URL — reconnect locally inside the container instead
+  args+=("$a")
+done
+container="rootnode-drill-postgres"
+needs_stdin=1
+for a in "${args[@]}"; do { [ "$a" = "-c" ] || [ "$a" = "-tAc" ]; } && needs_stdin=0; done
+if [ "$needs_stdin" = "1" ]; then
+  exec docker exec -e PGPASSWORD=postgres -i "$container" psql -h localhost -U postgres "${args[@]}"
+else
+  exec docker exec -e PGPASSWORD=postgres "$container" psql -h localhost -U postgres "${args[@]}"
+fi
+EOF
+  cat > "$SHIM_BIN/pg_dump" <<'EOF'
+#!/usr/bin/env bash
+args=()
+for a in "$@"; do
+  if [[ "$a" =~ ^postgres://[^:]+:[^@]+@[^:]+:([0-9]+)/(.*)$ ]]; then args+=("postgres://postgres:postgres@localhost:5432/${BASH_REMATCH[2]}"); continue; fi
+  args+=("$a")
+done
+exec docker exec -e PGPASSWORD=postgres rootnode-drill-postgres pg_dump "${args[@]}"
+EOF
+  chmod +x "$SHIM_BIN/psql" "$SHIM_BIN/pg_dump"
+  export PATH="$SHIM_BIN:$PATH"
+fi
+
+DB_URL="postgres://postgres:postgres@localhost:$PORT/postgres"
+
+echo "==> [1/9] Starting disposable Postgres"
+docker run -d --name "$CONTAINER" -e POSTGRES_PASSWORD=postgres -p "$PORT:5432" postgres:16-alpine >/dev/null
+for i in $(seq 1 30); do PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -c "SELECT 1" >/dev/null 2>&1 && break; sleep 1; done
+
+echo "==> [2/9] Applying real Provisioner + Platform API migrations"
+( cd platform/provisioner && [ -d node_modules ] || npm install --no-audit --no-fund >/dev/null
+  PLATFORM_DB_URL="$DB_URL" node -e "require('./src/db').runMigrations().then((m)=>console.log('  Provisioner:', m.join(', ')))" )
+( cd platform/api && [ -d node_modules ] || npm install --no-audit --no-fund >/dev/null
+  PLATFORM_DB_URL="$DB_URL" node -e "require('./src/db').runMigrations().then((m)=>console.log('  Platform API:', m.join(', ')))" )
+
+echo "==> [3/9] Bootstrapping the drill owner and starting a REAL Platform API"
+( cd platform/api && PLATFORM_DB_URL="$DB_URL" node bootstrap-owner.js [email protected] "Drill Owner" 'DrillOwnerPass!2026' )
+( cd platform/api && PLATFORM_DB_URL="$DB_URL" PROVISIONER_URL="http://localhost:1" PLATFORM_API_PORT="$API_PORT" node src/server.js > "$TESTDIR/api.log" 2>&1 & echo $! > "$TESTDIR/api.pid" )
+API_PID=$(cat "$TESTDIR/api.pid")
+for i in $(seq 1 30); do curl -sf "http://localhost:$API_PORT/healthz" >/dev/null 2>&1 && break; sleep 1; done
+curl -sf "http://localhost:$API_PORT/healthz" >/dev/null || { echo "FAIL: Platform API never came up"; cat "$TESTDIR/api.log"; exit 1; }
+echo "  Platform API up on :$API_PORT"
+
+echo "==> [4/9] Seeding realistic academy data through the real API (owner/admin/cohort/3 students/progress/attempts/assessment/achievements)"
+( cd infra/backup && PLATFORM_API_URL="http://localhost:$API_PORT" PLATFORM_DB_URL="$DB_URL" node seed-realistic-data.js )
+
+echo "==> [5/9] Backing up (real backup-postgres.sh)"
+BACKUP_DIR="$TESTDIR/backups" PLATFORM_DB_URL="$DB_URL" ./infra/backup/backup-postgres.sh
+ENC_FILE=$(ls "$TESTDIR"/backups/*.sql.gz.gpg | head -1)
+[ -f "$ENC_FILE" ] || { echo "FAIL: no encrypted backup produced"; exit 1; }
+
+echo "==> [6/9] DESTROYING the Postgres storage entirely (this is the destructive part — not restoring into a second container, the original is gone)"
+kill "$API_PID" 2>/dev/null || true; API_PID=""
+docker rm -f "$CONTAINER" >/dev/null
+echo "  source container + its storage are gone"
+
+echo "==> [7/9] Recreating Postgres from nothing"
+docker run -d --name "$CONTAINER" -e POSTGRES_PASSWORD=postgres -p "$PORT:5432" postgres:16-alpine >/dev/null
+for i in $(seq 1 30); do PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -c "SELECT 1" >/dev/null 2>&1 && break; sleep 1; done
+
+echo "==> [8/9] Restoring from the encrypted backup (schema + data both come from the dump — no separate migration step)"
+echo "RESTORE" | BACKUP_ENCRYPTION_PASSPHRASE="$BACKUP_ENCRYPTION_PASSPHRASE" ./infra/backup/restore-postgres.sh "$ENC_FILE" "$DB_URL"
+./infra/backup/verify-restore.sh "$DB_URL"
+
+echo "==> [9/9] Booting the REAL Platform API again against the RESTORED database"
+( cd platform/api && PLATFORM_DB_URL="$DB_URL" PROVISIONER_URL="http://localhost:1" PLATFORM_API_PORT="$API_PORT" node src/server.js > "$TESTDIR/api2.log" 2>&1 & echo $! > "$TESTDIR/api2.pid" )
+API_PID=$(cat "$TESTDIR/api2.pid")
+for i in $(seq 1 30); do curl -sf "http://localhost:$API_PORT/healthz" >/dev/null 2>&1 && break; sleep 1; done
+curl -sf "http://localhost:$API_PORT/healthz" >/dev/null || { echo "FAIL: Platform API did not come back up against the restored DB"; cat "$TESTDIR/api2.log"; exit 1; }
+echo "  Platform API is back up, against the RESTORED database — no fresh migration run needed"
+
+echo "==> Verifying accounts/RBAC/cohorts/students/progress/attempts/achievements survived"
+FAIL=0
+check() { local desc="$1" want="$2" got="$3"; if [ "$want" = "$got" ]; then echo "  ok — $desc"; else echo "  FAIL — $desc (want $want, got $got)"; FAIL=1; fi; }
+
+check "owner account (role) restored" "owner" "$(PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -tAc "SELECT role FROM instructors WHERE email='[email protected]'" | tr -d '[:space:]')"
+check "admin instructor restored" "admin" "$(PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -tAc "SELECT role FROM instructors WHERE email='[email protected]'" | tr -d '[:space:]')"
+check "cohort restored" "1" "$(PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -tAc "SELECT count(*) FROM cohorts WHERE cohort_id='drill-cohort-01'" | tr -d '[:space:]')"
+check "3 students restored" "3" "$(PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -tAc "SELECT count(*) FROM cohort_enrollments WHERE cohort_id='drill-cohort-01'" | tr -d '[:space:]')"
+check "3 completed attempts restored" "3" "$(PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -tAc "SELECT count(*) FROM scenario_attempts WHERE result='passed' AND scenario_id='pod-basics-mcq'" | tr -d '[:space:]')"
+check "3 achievements restored" "3" "$(PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -tAc "SELECT count(*) FROM achievements WHERE stage_id='foundation'" | tr -d '[:space:]')"
+check "assessment definition restored" "1" "$(PGPASSWORD=postgres psql -h localhost -p "$PORT" -U postgres -tAc "SELECT count(*) FROM assessment_definitions WHERE assessment_definition_id='drill-exam-01'" | tr -d '[:space:]')"
+
+echo "==> Verifying RBAC still works against the restored DB (real login through the real API)"
+LOGIN_STATUS=$(curl -s -o /dev/null -w '%{http_code}' -X POST "http://localhost:$API_PORT/api/auth/instructor/login" \
+  -H 'Content-Type: application/json' -d '{"email":"[email protected]","password":"DrillAdminPass!2026"}')
+check "restored admin instructor can log in" "200" "$LOGIN_STATUS"
+
+if [ "$FAIL" = "1" ]; then
+  echo; echo "DRILL FAILED — see above."; exit 1
+fi
+
+echo
+echo "OK: full destructive restore drill passed — owner/admin/cohort/3 students/progress/attempts/"
+echo "assessment/achievements all survived a real Postgres storage loss + recreation + restore, and"
+echo "the real Platform API booted and authenticated against the restored database with no fresh"
+echo "migration run required."
+echo "NOT TESTED HERE (needs real credentials/hardware): the actual off-host Storage Box/S3 copy."

infra/backup/verify-restore.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Sanity-checks a restored database — confirms the expected Platform API schema landed and has
+# data, not just that psql exited 0 (a restore that silently imported zero rows would still
+# "succeed" by that measure). Used both by restore-postgres.sh's own suggestion and by
+# test-backup-restore.sh's automated local test.
+set -euo pipefail
+DB_URL="${1:?usage: verify-restore.sh <db-url>}"
+
+EXPECTED_TABLES=(students cohorts instructors sessions scenario_attempts assessment_definitions achievements audit_events)
+FAIL=0
+
+for t in "${EXPECTED_TABLES[@]}"; do
+  exists=$(psql "$DB_URL" -tAc "SELECT to_regclass('public.$t') IS NOT NULL")
+  if [ "$exists" != "t" ]; then
+    echo "MISSING TABLE: $t" >&2
+    FAIL=1
+  fi
+done
+
+if [ "$FAIL" = "1" ]; then
+  echo "FAIL: restored database is missing expected tables" >&2
+  exit 1
+fi
+
+MIGRATIONS_APPLIED=$(psql "$DB_URL" -tAc "SELECT count(*) FROM schema_migrations" 2>/dev/null || echo 0)
+echo "OK: all expected tables present. $MIGRATIONS_APPLIED migrations recorded in schema_migrations."

infra/ci/gitea-workflows/build-and-test.yml

@@ -0,0 +1,162 @@
+# Gitea Actions workflow — build/test on every push to main. Gitea Actions uses the same
+# workflow syntax as GitHub Actions (a compatible runner), so this is portable if the canonical
+# remote ever needs to move CI providers, without being GitHub Actions itself or requiring a
+# paid CI provider. Runs against the canonical Gitea repo only — see docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md
+# §18 for why this never touches the GitHub kubekosh fork.
+#
+# Deploy this file to .gitea/workflows/build-and-test.yml at the repo root to activate it (kept
+# under infra/ci/ in this PR so it's reviewed alongside the rest of the infra package first,
+# per the same "build now, activate deliberately" posture as everything else server-dependent
+# in this phase — enabling Gitea Actions on the instance is itself a one-time admin step that
+# may not be done yet).
+
+name: build-and-test
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  regression:
+    runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgres:16-alpine
+        env:
+          POSTGRES_PASSWORD: postgres
+        ports: ["5432:5432"]
+        options: >-
+          --health-cmd "pg_isready -U postgres"
+          --health-interval 10s --health-timeout 5s --health-retries 10
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+
+      - name: Install dependencies (all first-party services)
+        run: |
+          for d in backend frontend platform/api platform/gateway platform/provisioner platform/lab-router; do
+            (cd "$d" && npm ci)
+          done
+
+      - name: Syntax-check every service
+        run: |
+          for d in backend frontend/src platform/api platform/gateway platform/provisioner platform/lab-router; do
+            find "$d" -name '*.js' -not -path '*/node_modules/*' -exec node --check {} \;
+          done
+
+      - name: Lab Host Router unit tests (Phase 4.1 — fast, no Docker daemon needed)
+        run: (cd platform/lab-router && npm test)
+
+      - name: Build frontend
+        run: (cd frontend && npm run build)
+
+      - name: Provisioner migrations against the service Postgres
+        run: |
+          cd platform/provisioner
+          PLATFORM_DB_URL=postgres://postgres:postgres@localhost:5432/postgres \
+            node -e "require('./src/db').runMigrations().then(m=>console.log('Applied:',m.join(', ')))"
+
+      - name: Platform API migrations (depends on Provisioner's, same order as production)
+        run: |
+          cd platform/api
+          PLATFORM_DB_URL=postgres://postgres:postgres@localhost:5432/postgres \
+            node -e "require('./src/db').runMigrations().then(m=>console.log('Applied:',m.join(', ')))"
+
+      - name: Validate infra configs (Phase 4 local tests — no hardware needed)
+        run: |
+          ./infra/scripts/validate-compose.sh
+          ./infra/firewall/validate-firewall.sh
+
+      # The real k3s-boot-dependent e2e suites (platform/test/e2e-phase*.js) need a full Docker
+      # Compose stack with --privileged Lab containers, which a shared CI runner typically
+      # can't grant safely — they stay a LOCAL/staging pre-promotion step
+      # (infra/scripts/staging-smoke-test.sh), not this job. See docs/PHASE4_PRODUCTION_INFRASTRUCTURE.md §18.
+
+  # Phase 4.1 §24 — free/open-source security scanning, no paid tooling, no signup required for
+  # any of these. Severity policy (docs/SECURITY_SCANNING.md): CRITICAL/HIGH findings fail the
+  # build; MEDIUM/LOW are reported but never block a merge — a build that's permanently red over
+  # an unrelated low-severity transitive dependency finding trains everyone to ignore red builds.
+  security-scan:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+
+      - name: npm audit (dependency vulnerabilities) — fails only on high/critical
+        run: |
+          FAIL=0
+          for d in backend frontend platform/api platform/gateway platform/provisioner platform/lab-router; do
+            echo "== $d =="
+            (cd "$d" && npm audit --audit-level=high) || FAIL=1
+          done
+          exit $FAIL
+
+      - name: Secret scanning (gitleaks — free, no account needed)
+        run: docker run --rm -v "$PWD:/repo" zricethezav/gitleaks:latest detect --source=/repo --no-git -v
+
+      - name: Dockerfile linting (hadolint — free)
+        run: |
+          FAIL=0
+          for f in Dockerfile platform/api/Dockerfile platform/gateway/Dockerfile platform/provisioner/Dockerfile platform/egress-proxy/Dockerfile platform/lab-router/Dockerfile; do
+            echo "== $f =="
+            docker run --rm -i hadolint/hadolint < "$f" || FAIL=1
+          done
+          exit $FAIL
+
+      # -S error, not warning — matches docs/SECURITY_SCANNING.md's severity policy. Real run
+      # against this tree at -S warning surfaces only style nits (unused loop vars, a missing
+      # `cd ... || exit` guard) on scripts that are otherwise correct; failing the build on
+      # those trains everyone to ignore the check.
+      - name: Shell linting (shellcheck — free, standard)
+        run: |
+          sudo apt-get update -qq && sudo apt-get install -y -qq shellcheck
+          find infra -name '*.sh' -exec shellcheck -S error {} \+
+
+      - name: Container image scanning (trivy — free, no account needed)
+        run: |
+          docker build -q -t rootnode-scan/platform-api -f platform/api/Dockerfile .
+          docker run --rm -v /var/run/docker.sock:/var/run/docker.sock aquasec/trivy:latest image \
+            --severity HIGH,CRITICAL --exit-code 1 rootnode-scan/platform-api
+
+  build-images:
+    needs: [regression, security-scan]
+    if: github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build and tag images
+        run: ./infra/scripts/ci/tag-and-push.sh
+        env:
+          REGISTRY: ${{ vars.REGISTRY }}
+          REGISTRY_USER: ${{ secrets.REGISTRY_USER }}
+          REGISTRY_PASSWORD: ${{ secrets.REGISTRY_PASSWORD }}
+
+  deploy-staging:
+    needs: build-images
+    if: github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Deploy to staging (automatic)
+        run: |
+          cd infra/ansible
+          ansible-playbook site.yml -i inventory/staging.ini \
+            -e "image_tag=staging-${GITHUB_SHA::12}" \
+            --vault-password-file <(echo "$VAULT_PASSWORD")
+        env:
+          VAULT_PASSWORD: ${{ secrets.ANSIBLE_VAULT_PASSWORD }}
+
+      - name: Staging smoke test
+        run: ./infra/scripts/staging-smoke-test.sh
+
+  # Production is NEVER automatic — a human runs infra/scripts/deploy-production.sh after
+  # reviewing the staging smoke test result, per the explicit "manual approval step" preference.
+  # No job here does that; see docs/RUNBOOK_NORMAL_DEPLOY.md for the actual command.