fix(fc5): ruff (E712, ASYNC230/240, I001) + Credential.credential_type + FileStorage in api_migrate test

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/tasks/migration.py

@@ -20,15 +20,10 @@ from ..celery_app import celery
 from ..config import get_config
 from ..models import MigrationRun
 from ..services.credential_crypto import CredentialCrypto
-from ..services.migrators import (
-    backup as backup_mod,
-    gs_ingest,
-    ir_ingest,
-    ml_queue,
-    rollback as rollback_mod,
-    tag_apply,
-    verify,
-)
+from ..services.migrators import backup as backup_mod
+from ..services.migrators import gs_ingest, ir_ingest, ml_queue
+from ..services.migrators import rollback as rollback_mod
+from ..services.migrators import tag_apply, verify
 
 log = logging.getLogger(__name__)