A01: Per-source health affects community_scheduler overall status

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

apps/api/app/readiness.py

@@ -72,11 +72,14 @@ def readiness_report(
 
     # Community scheduler health — diagnostic only, never blocks readiness (A01)
     # Track per-source health with rotation, backoff, last success, and stalled attempts
+    # Overall status reflects worst-case source health (success of one does not mask failure of another)
     try:
         enabled_sources = list(session.scalars(
             select(DataSource).where(DataSource.enabled.is_(True)).order_by(DataSource.key)
         ))
         source_health: dict[str, dict[str, object]] = {}
+        has_any_failure = False
+        has_any_success = False
         for source in enabled_sources:
             latest_run = session.scalar(
                 select(CommunityImportRun)
@@ -108,7 +111,18 @@ def readiness_report(
                 "backoff_recommended": recent_failures >= 5,
                 "blocking": False,
             }
-        components["community_scheduler"] = {"status": "ready", "sources": source_health}
+            if healthy:
+                has_any_success = True
+            elif latest_run.status == "failed":
+                has_any_failure = True
+        # Overall status: "degraded" if any source failed, "ready" if all healthy, "stale" if no failures but stale
+        if has_any_failure:
+            scheduler_status = "degraded"
+        elif has_any_success:
+            scheduler_status = "ready"
+        else:
+            scheduler_status = "stale" if enabled_sources else "not_started"
+        components["community_scheduler"] = {"status": scheduler_status, "sources": source_health}
     except Exception:
         components["community_scheduler"] = {"status": "unknown", "sources": {}}