style: apply ruff formatting to all backend files

backend/routes/health.py

@@ -1,4 +1,3 @@
-
 from auth import require_auth
 from fastapi import APIRouter, Depends
 from models.api import SourceHealthResponse
@@ -19,17 +18,21 @@ def source_health():
             status = doc.get("status")
             if not status:
                 status = "healthy" if doc.get("last_fetch_time") else "unknown"
-            results.append({
-                "source": source,
-                "last_fetch_time": doc.get("last_fetch_time"),
-                "last_attempt_time": doc.get("last_attempt_time"),
-                "status": status,
-            })
+            results.append(
+                {
+                    "source": source,
+                    "last_fetch_time": doc.get("last_fetch_time"),
+                    "last_attempt_time": doc.get("last_attempt_time"),
+                    "status": status,
+                }
+            )
         else:
-            results.append({
-                "source": source,
-                "last_fetch_time": None,
-                "last_attempt_time": None,
-                "status": "unknown",
-            })
+            results.append(
+                {
+                    "source": source,
+                    "last_fetch_time": None,
+                    "last_attempt_time": None,
+                    "status": "unknown",
+                }
+            )
     return results