When all services in a Docker Compose file have `exclude_from_hc: true`,
the status aggregation logic was returning invalid states causing broken UI.
**Problems fixed:**
- ComplexStatusCheck returned 'running:healthy' for apps with no monitored containers
- Service model returned ':' (null status) when all services excluded
- UI showed active start/stop buttons for non-running services
**Changes:**
- ComplexStatusCheck: Return 'exited:healthy' when relevantContainerCount is 0
- Service model: Return 'exited:healthy' when both status and health are null
- Added comprehensive unit tests to verify the fixes
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
