Document the six-case self-hosted diagnosis drill

[rmcdaniel]

Customer outcome

Add the reusable self-hosted diagnosis procedure from #143. It gives CLI/API/Waterline observations, safe actions and verification for all six requested failures, plus a reproducible reporting method.

The published fixes are delivered in Waterline 2.0.8, CLI 2.1.3 and Server 2.4.31. A fresh focused six-case pass uses those artifacts with published PHP SDK 2.1.6 and verifies original-run results, histories and actual diagnosis/recovery intervals. Detailed sanitized evidence is being retained on #143.

This is documentation. It does not change the protocol catalog, introduce another runner, or claim an independent blind study. Normal repository CI and full diff review are required. #143 will close after the guide is merged, final evidence is verified and task resources are removed.

[rmcdaniel]

Reviewed the complete diff at 2e00da951791562c474ea8685ec1af62cb97f230. The guide uses published operator commands, distinguishes heartbeat freshness from process liveness, preserves original run identities and lease fencing, and explains connection-only readiness and safe storage recovery. It links the drill as operator experience without adding an unexecuted stable protocol catalog claim.

Normal Shared contract tests pass. The fresh published-artifact pass verifies all six original runs, one completion each, exact results and actual UTC diagnosis/recovery intervals. No prose-mirroring tests are needed for this documentation change. Merge the guide, verify the public document and clean the experiment resources before closing #143.