feat(ha-diag-agent): UnavailableEntitiesCheck with root cause dedup
- shared aiohttp ClientSession in HAClient (Phase 1 Flag #2 fixed):
make_session() factory, session injected at startup, closed on shutdown
- Check.run() → list[CheckResult]: clean multi-event interface
- first real diagnostic check: entity unavailable > 24h
(INSERT OR IGNORE baseline preserves first-seen timestamp)
- root cause grouping: emit ha_integration_failed instead of N entity
events when ≥50% of integration's entities are unavailable (≥3 min)
- alert deduplication via SQLite cooldown window (default 6h)
- recovery clears baseline + dedup for immediate re-alert
- configurable thresholds: duration, integration %, cooldown
- 38 unit tests + 7 integration tests (42 pass, 3 skip w/o live HA)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Oskar Kapala
20f6761a67