A01: Fix scheduler aggregation to not mask stale/failed sources

Bug: has_any_success allowed one healthy source to give overall 'ready'
when another source was stale/not_started/running — masking failures.

Fix:
- Added has_any_stale and has_any_running tracking
- Overall status is 'degraded' if ANY source is failed/stale/running
- Overall status is 'ready' ONLY when ALL enabled sources are healthy
- 'not_started' when no sources are enabled
- readiness (ready flag) still NOT blocked by import health (A01 requirement)

Verification:
- 7/7 readiness tests pass
- 124/124 Python tests pass (1 skipped)
- Stale source now shows 'degraded' instead of 'ready'
- Failed source still shows 'degraded'
- All healthy sources show 'ready'

apps/api/tests/test_readiness.py

@@ -123,7 +123,7 @@ def test_community_scheduler_stale_does_not_block_readiness() -> None:
             import_interval_seconds=3600, community_import_interval_seconds=1800, now=now,
         )
     assert ready is True  # A01: stale does NOT block readiness
-    assert components["community_scheduler"]["status"] == "stale"  # Overall reflects stale source
+    assert components["community_scheduler"]["status"] == "degraded"  # Stale source shows as degraded
     assert components["community_scheduler"]["sources"]["rf4db"]["status"] == "stale"
     assert components["community_scheduler"]["sources"]["rf4db"]["blocking"] is False