[Milestone v3][P3] Failure-recovery playbook for autonomous loop

[imKXNNY]

Summary

Create a failure-recovery playbook for autonomous loop operations (rate limits, flaky checks, webhook replays, stuck runs).

Scope

• Define incident classes and triage matrix
• Add retry/backoff and dead-letter handling guidance
• Add operational commands/runbook snippets
• Define escalation and stop-the-loop criteria

Acceptance Criteria

• Playbook exists under docs with concrete command examples.
• Recovery procedures cover 429, webhook duplicate/replay, and check-timeout paths.
• Stop/resume criteria are explicit and testable.
• Linked from README ops/automation section.

Priority

P3