docs(troubleshooting): add common issues guide and diagnostic playbook (P11.5)
Implements P11.5 acceptance criteria:
- Created docs/troubleshooting.md with 10 common issues
- Created docs/troubleshooting/diagnostics.md with systematic diagnostic playbook
- Documented 3 required plan §11 issues (primary key required, degraded search results, stuck tasks)
- Added 7 additional issues from Phase 9 chaos testing and operations
- Cross-linked from README, migration runbook, and dump import guide
Documented issues:
1. "primary key required" - Miroir vs Meilisearch difference
2. Search returns fewer results - degraded node handling
3. Task polling stuck - per-node task status recovery
4. Node drain blocked - RF constraints
5. Migration stuck after coordinator crash - recovery procedures
6. High memory usage on Redis - cleanup procedures
7. Index creation fails - topology inconsistency
8. Alias flip conflicts - single vs multi alias types
9. Search timeout during migration - throttling options
10. CDC cursor out of sync - recovery and re-index
Diagnostic playbook covers:
- Cluster health checks (pods, nodes, resources)
- Topology verification and node agreement
- Metrics analysis (degraded shards, task queue, latency)
- Log analysis for error patterns
- Task status inspection
- Anti-entropy status
- External dependency checks
- Self-diagnostics and canary tests
Closes: miroir-uyx.5
c5238b1bcd