- AgentRegistryService: register, heartbeat, lifecycle, commands
- ConcurrentHashMap with atomic record-swapping for thread safety
- LIVE->STALE->DEAD lifecycle transitions via checkLifecycle()
- Heartbeat revives STALE agents back to LIVE
- Command queue with PENDING/DELIVERED/ACKNOWLEDGED/EXPIRED states
- AgentEventListener callback for SSE bridge integration
- All 23 unit tests pass
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>