refactor: standardize runtime annotation types across multiple files

backend/app/schemas/gateways.py

@@ -2,12 +2,14 @@
 
 from __future__ import annotations
 
-from datetime import datetime  # noqa: TCH003
-from uuid import UUID  # noqa: TCH003
+from datetime import datetime
+from uuid import UUID
 
 from pydantic import field_validator
 from sqlmodel import Field, SQLModel
 
+RUNTIME_ANNOTATION_TYPES = (datetime, UUID)
+
 
 class GatewayBase(SQLModel):
     """Shared gateway fields used across create/read payloads."""