feat(admin): notification operations — resend activation, delivery status, RBAC-scoped views

- notification-routes.js: global list (owner/admin only), per-student list (scoped via
  requireStudentRelationshipAccess), resend-activation (mechanically the same as
  regenerate — Phase 5A's token model already guarantees only the latest is ever valid, so one
  action covers both), a dev-only preview route (unconditionally refuses when
  COOKIE_SECURE=1, mirroring student-auth-routes.js's existing dev_reset_token gate).
- NotificationsView.jsx: owner/admin global notification list, paginated, matching
  AuditView.jsx's exact convention.
- StudentsView.jsx: student detail gained a Resend activation control and a Notifications
  history card; Credentials card now explains the automatic-email behavior.
- AdminPortal.jsx: new Notifications nav entry (owner/admin only).

platform/api/src/notification-routes.js

@@ -0,0 +1,118 @@
+// Phase 5C §15/§16 — instructor/admin communication operations. Global notification visibility
+// is owner/admin only (§16: "Do not grant global notification visibility to every instructor");
+// a plain instructor can still see/act on notifications for a SPECIFIC student they're
+// authorized to manage via rbac.js's requireStudentRelationshipAccess (cohort-shared or an
+// enrollment they created — the same rule admin-programs-routes.js already established for
+// enrollment visibility). Every response here goes through notifications.js's toAdminView,
+// which masks the recipient address and omits `metadata` entirely — no token, no full email,
+// ever, through any route in this file.
+
+const notificationsLib = require('./notifications');
+const enrollmentLib = require('./enrollment');
+const programsLib = require('./programs');
+const studentsAuth = require('./students-auth');
+const { parsePagination, paginatedResponse } = require('./pagination');
+
+module.exports = function registerNotificationRoutes(app, deps) {
+  const { instructorSession, rbac, getPool, recordAudit } = deps;
+  const { requireAdminOrOwner, requireStudentRelationshipAccess } = rbac;
+
+  function wrap(fn) {
+    return (req, res, next) => { Promise.resolve(fn(req, res, next)).catch(next); };
+  }
+  const admin = {
+    get: (p, ...mw) => app.get(p, instructorSession, ...mw.map(wrap)),
+    post: (p, ...mw) => app.post(p, instructorSession, ...mw.map(wrap)),
+  };
+
+  // Global operational view — owner/admin only.
+  admin.get('/api/admin/notifications', requireAdminOrOwner, async (req, res) => {
+    const pool = getPool();
+    const { page, pageSize, offset } = parsePagination(req);
+    const [{ rows }, { rows: countRows }] = await Promise.all([
+      pool.query(`SELECT * FROM notification_events ORDER BY created_at DESC LIMIT $1 OFFSET $2`, [pageSize, offset]),
+      pool.query(`SELECT count(*)::int AS n FROM notification_events`),
+    ]);
+    res.json(paginatedResponse(rows.map(notificationsLib.toAdminView), countRows[0].n, { page, pageSize }));
+  });
+
+  // Per-student view — the scoped surface a plain instructor can actually reach.
+  admin.get('/api/admin/students/:id/notifications', requireStudentRelationshipAccess('id'), async (req, res) => {
+    const rows = await notificationsLib.listForStudent(getPool(), req.params.id);
+    res.json(rows.map(notificationsLib.toAdminView));
+  });
+
+  // §20 — dev/test ONLY: lets a test script (or a developer) see exactly what the dev provider
+  // would have sent, including the activation/reset URL, without a real inbox. Unconditionally
+  // refuses in production regardless of what's stored (mirrors student-auth-routes.js's
+  // dev_reset_token gate on the same COOKIE_SECURE-derived signal) — this is never how an
+  // admin inspects a real delivery, only how a dev/CI run verifies one.
+  admin.get('/api/admin/notifications/:id/dev-preview', requireAdminOrOwner, async (req, res) => {
+    if (process.env.COOKIE_SECURE === '1') return res.status(404).json({ error: 'not_found' });
+    const preview = await notificationsLib.getDevPreview(getPool(), req.params.id);
+    if (!preview) return res.status(404).json({ error: 'no_preview_available' });
+    res.json(preview);
+  });
+
+  // §15 — one action covers both "resend" and "regenerate": Phase 5A's issueCredentialToken
+  // already unconditionally invalidates any previous outstanding token on mint, so there is
+  // never a moment with two simultaneously valid activation links — a second button that did
+  // something different would have nothing different to do. See
+  // docs/PHASE5C_ENROLLMENT_COMMUNICATIONS.md §6 for the full reasoning.
+  admin.post('/api/admin/students/:id/resend-activation', requireStudentRelationshipAccess('id'), async (req, res) => {
+    const pool = getPool();
+    const { rows } = await pool.query(`SELECT student_id, display_name, password_hash FROM students WHERE student_id = $1`, [req.params.id]);
+    if (!rows.length) return res.status(404).json({ error: 'not found' });
+    if (rows[0].password_hash) return res.status(409).json({ error: 'already_activated', message: 'This student already has real credentials — use Send Password Reset instead.' });
+
+    const { rows: enrollmentRows } = await pool.query(
+      `SELECT enrollment_id, program_id FROM enrollments WHERE student_id = $1 ORDER BY enrolled_at DESC LIMIT 1`, [req.params.id]
+    );
+    const enrollmentId = enrollmentRows[0]?.enrollment_id || null;
+    const program = enrollmentRows[0] ? await programsLib.getProgram(pool, enrollmentRows[0].program_id) : null;
+
+    const notification = await notificationsLib.notifyForEnrollment(pool, studentsAuth, {
+      studentId: req.params.id, enrollmentId, programName: program?.name, isResend: true,
+    });
+    await recordAudit(pool, { actorType: 'instructor', actorId: req.instructor.instructor_id, action: 'activation_resent', resourceType: 'student', resourceId: req.params.id, result: 'success', sourceIp: req.ip });
+    res.json(notificationsLib.toAdminView(notification));
+  });
+
+  admin.post('/api/admin/students/:id/send-enrollment-confirmation', requireStudentRelationshipAccess('id'), async (req, res) => {
+    const pool = getPool();
+    const { enrollment_id } = req.body || {};
+    const { rows } = await pool.query(`SELECT student_id, display_name, password_hash FROM students WHERE student_id = $1`, [req.params.id]);
+    if (!rows.length) return res.status(404).json({ error: 'not found' });
+    if (!rows[0].password_hash) return res.status(409).json({ error: 'not_yet_activated', message: 'This student has no credentials yet — use Resend Activation instead.' });
+
+    let targetEnrollmentId = enrollment_id;
+    if (!targetEnrollmentId) {
+      const { rows: latest } = await pool.query(
+        `SELECT enrollment_id FROM enrollments WHERE student_id = $1 AND status = 'active' ORDER BY enrolled_at DESC LIMIT 1`, [req.params.id]
+      );
+      targetEnrollmentId = latest[0]?.enrollment_id;
+    }
+    if (!targetEnrollmentId) return res.status(400).json({ error: 'no_active_enrollment', message: 'This student has no active enrollment to confirm.' });
+    const enrollmentRow = await enrollmentLib.getEnrollment(pool, targetEnrollmentId);
+    const program = await programsLib.getProgram(pool, enrollmentRow.program_id);
+
+    const notification = await notificationsLib.enqueue(pool, {
+      studentId: req.params.id, enrollmentId: targetEnrollmentId, notificationType: 'enrollment_confirmation',
+      metadata: { display_name: rows[0].display_name, program_name: program?.name },
+    });
+    await recordAudit(pool, { actorType: 'instructor', actorId: req.instructor.instructor_id, action: 'enrollment_confirmation_sent', resourceType: 'enrollment', resourceId: targetEnrollmentId, result: 'success', sourceIp: req.ip });
+    res.json(notificationsLib.toAdminView(notification));
+  });
+
+  // §8/§15's "admin may need a safe SEND PASSWORD RESET operation" is the EXISTING
+  // POST /api/admin/students/:id/reset-password (admin-routes.js, Phase 5A) — Phase 5C extended
+  // it to also enqueue a real email (see that route) rather than duplicating a second endpoint
+  // here. It still returns `reset_token` in its response, unchanged from Phase 5A: for a
+  // student with no deliverable address at all (no email, no enrollment contact), manually
+  // relaying that token is the ONLY way they can ever get in, so removing it would leave that
+  // population with no recovery path. §21's "admin cannot view token" is enforced for
+  // resend-activation/send-enrollment-confirmation above, which have no legitimate reason to
+  // ever expose one — reset-password's token-in-response is a deliberate, documented,
+  // unchanged exception for exactly the case automatic delivery can't cover. See
+  // docs/PHASE5C_ENROLLMENT_COMMUNICATIONS.md §6.
+};