chore: add ast-grep rule to convert Optional[T] to T | None (#25560)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/services/agent_service.py

@@ -1,5 +1,5 @@
 import threading
-from typing import Any, Optional
+from typing import Any
 
 import pytz
 
@@ -35,7 +35,7 @@ class AgentService:
         if not conversation:
             raise ValueError(f"Conversation not found: {conversation_id}")
 
-        message: Optional[Message] = (
+        message: Message | None = (
             db.session.query(Message)
             .where(
                 Message.id == message_id,