feat(root): author the health-probes gold-standard module

content/root/root-10-kubernetes-troubleshooting-observability/m01-health-probes/: lesson (probe concepts) -> demonstration (reading kubectl describe pod Events for a probe failure) -> knowledge check -> guided exercise (write a readiness probe on paper) -> Launch Lab intro (rootnode-probe-port-mismatch) -> reflection (root cause + Real Ops prevention takeaway). 5 of 6 activities carry instructor notes (demo plan, misconceptions, timing, discussion questions, extensions). This is the reference implementation docs/COURSE_AUTHORING_STANDARD.md documents for all future RootNode lesson authoring. Co-Authored-By: Claude Sonnet 5 <[email protected]>
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+# Launch Lab: Stuck Not-Ready: The Probe Port Mismatch
+
+Time to apply everything from this module against a real, running incident — not a diagram, an
+actual Deployment in your own disposable Lab environment.
+
+## What you're walking into
+
+A deployment called `api-gateway` has been rolled out. The pods start, the container runs — but
+the deployment never reaches Ready, and traffic isn't being routed to it. Somewhere on-call, an
+alert is firing.
+
+You now have everything you learned in this module to work with:
+
+- **The lesson** told you what "stuck at 0/2 Ready with 0 restarts" actually means (a readiness
+  problem, not a crash).
+- **The demonstration** showed you exactly where to look for the explanation — `kubectl get
+  pods`, then `kubectl describe pod` and its Events section — and what a port-mismatch failure
+  looks like in that output.
+- **The guided exercise** had you reason through what a correct probe definition looks like,
+  which is exactly what you'll need to compare the broken one against.
+
+## Your task in this Lab
+
+Diagnose why the pods are failing their readiness check, correct the probe configuration, and
+restore the deployment to fully Ready. Start with pod status and events, the same way you just
+practiced — read before you patch.
+
+This Lab has its own in-context hints if you get stuck, revealed one at a time — use the
+concepts from this module first; reach for a hint only if you're genuinely stuck, not as the
+first move.
+
+When the Lab confirms your fix, come back to this module to close it out with a short
+reflection on what actually caused this.
+
+## Instructor Notes
+
+**Classroom flow:** if teaching this live, this is the natural point to have students launch
+their own Lab environment and work independently or in pairs, while you circulate. The
+Real-Time Classroom dashboard's help-request and progress views (see the instructor Curriculum
+view) show who's stuck without needing to walk around asking.
+
+**Approximate timing:** 15-20 minutes for most students; some will resolve it in under 5 once
+the module's concepts have landed.
+
+**Common mistake to watch for:** students jumping straight to `kubectl logs` here, which will
+be unhelpful (nginx has nothing to say about a probe pointed at the wrong port) — this is a good
+moment to reinforce the demonstration's point about reading Events first for this failure class.