Implements production-ready lifecycle management with graceful shutdown
and comprehensive health monitoring:
Health Check Endpoints:
- /health/detailed - Comprehensive health with service statuses (200/503)
- /ready - Readiness probe for Kubernetes/Docker
- /live - Liveness probe with shutdown awareness
- /health/shutdown - Debug endpoint for shutdown status
Graceful Shutdown:
- Signal handlers for SIGTERM/SIGINT in lifespan manager
- Thread-safe shutdown state tracking
- Readiness probe returns 503 during shutdown
- Liveness probe detects shutdown timeout
- Proper cleanup of background tasks and connections
Acceptance Criteria:
✓ Graceful shutdown implemented for all services
✓ Health check endpoints respond with proper status codes
✓ Readiness probe indicates when service is ready for traffic
✓ Liveness probe detects when service needs restart
✓ Signal handling works in container environments
Fixes#1397