Revert "fix: ruff"

This reverts commit 7cd23900f3.

src/plugins/PFC/chat_observer.py

@@ -1,10 +1,12 @@
 import time
+import datetime
 import asyncio
 from typing import Optional, Dict, Any, List
 from src.common.logger import get_module_logger
 from src.common.database import db
 from ..message.message_base import UserInfo
 from ..config.config import global_config
+from ..chat.message import Message
 
 logger = get_module_logger("chat_observer")