Update health endpoint with data-sources route

backend/api/routes/health.py

@@ -95,3 +95,13 @@ async def health_data(hub: DataHub = Depends(get_datahub)):
 
     all_ok = all(s.get("ok", False) for s in sources.values())
     return {"status": "ok" if all_ok else "degraded", "sources": sources}
+
+
+@router.get("/health/data-sources")
+async def health_data_sources(hub: DataHub = Depends(get_datahub)):
+    """Per-source data flow status with green/yellow/red classification."""
+    from backend.services.data_flow_monitor import DataFlowMonitor
+
+    loop = asyncio.get_event_loop()
+    monitor = DataFlowMonitor()
+    return await loop.run_in_executor(None, monitor.check_all, hub)