## Changes
- Remove `activeSessions` parameter from health check (was never populated)
- Add gateway session lookup via `openclaw gateway call status`
- Add issue label lookup via `provider.getIssue(issueId)`
- Implement detection matrix with 6 issue types:
- session_dead: active worker but session missing in gateway
- label_mismatch: active worker but issue not in Doing/Testing
- stale_worker: active for >2h
- stuck_label: inactive but issue has Doing/Testing label
- orphan_issue_id: inactive but issueId set
- issue_gone: active but issue deleted/closed
## Files
- lib/services/health.ts — complete rewrite with three-source triangulation
- lib/tools/health.ts — remove activeSessions param, fetch sessions from gateway
- lib/services/heartbeat.ts — remove empty activeSessions calls, pass sessions map
- Introduced a new heartbeat service that runs at defined intervals to perform health checks on workers and fill available task slots based on priority.
- Added a health tool to scan worker health across projects with optional auto-fix capabilities.
- Updated the status tool to provide a lightweight overview of worker states and queue counts without health checks.
- Enhanced task creation tool descriptions to clarify task state handling.
- Implemented tests for the work heartbeat logic, ensuring proper project resolution, worker state management, and task prioritization.
