Bug: community_scheduler always had status='ready' even when individual
sources were failed or stale. Success of one source masked failure of another.
Fix:
- Overall status is 'degraded' if any enabled source has failed
- Overall status is 'stale' if all sources are stale but none failed
- Overall status is 'ready' only when at least one source is healthy
- Overall status is 'not_started' when no sources are enabled
- Readiness (ready flag) still NOT blocked by import health (A01 requirement)
Verification:
- 7/7 readiness tests pass
- 121/121 Python tests pass (1 skipped)
- Failed/stale sources are now visible in JSON without blocking scheduler
ik
f2ad5ecfa3