refactor: unify skills+cli runtime and streamline ag-ui flow

backend/tests/unit/v1/agent/test_attachment_storage.py

@@ -38,12 +38,12 @@ async def test_attachment_storage_rejects_unexpected_bucket(
 
     storage = SupabaseService()
     monkeypatch.setattr(
-        app_config.storage,
+        app_config.storage.attachment,
         "bucket",
         "allowed-bucket",
     )
 
-    with pytest.raises(RuntimeError, match="Invalid attachment bucket"):
+    with pytest.raises(RuntimeError, match="Invalid storage bucket"):
         await storage.upload_bytes(
             bucket="other-bucket",
             path="agent-inputs/u/t/r/file.png",
@@ -62,7 +62,7 @@ async def test_attachment_storage_accepts_configured_bucket(
     fake_bucket = _FakeBucket()
     fake_client = SimpleNamespace(storage=_FakeStorage(fake_bucket))
     monkeypatch.setattr(
-        app_config.storage,
+        app_config.storage.attachment,
         "bucket",
         "allowed-bucket",
     )