优化代码，删除无效代码

robot.py

@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-import re
 import time
 import asyncio
 import threading
@@ -23,7 +22,6 @@ from utils.revoke.message_auto_revoke import MessageAutoRevoke
 from utils.robot_cmd.robot_command import GroupBotManager, Feature, PermissionStatus
 
 from db.connection import DBConnectionManager
-from message_util import MessageUtil
 from db.contacts_db import ContactsDBOperator
 from utils.wechat.contact_manager import ContactManager
 from utils.wechat.message_to_db import MessageStorage
@@ -81,15 +79,13 @@ class Robot(Job):
         self.event_system = EventSystem()
         self.plugin_modules = {}  # 存储已加载的插件模块
         self.plugins = {}  # 存储已加载的插件实例
-        self.message_util = None
         # 设置插件系统上下文
         self.system_context = {
             "config": config,
             "event_system": self.event_system,
             "plugin_registry": self.plugin_registry,
             "db_pool": self.db_pool,
-            "redis_pool": self.redis_pool,
-            "message_util": self.message_util
+            "redis_pool": self.redis_pool
         }
 
         self.plugin_manager = PluginManager(plugin_dir=getattr(self.config, "plugin_dir", "plugins"))
@@ -185,8 +181,6 @@ class Robot(Job):
 
             self.message_storage = MessageStorage(self.ipad_bot)
 
-            # 初始化消息工具类 - 使用联系人管理器
-            self.message_util = MessageUtil(self.ipad_bot)
             # 先接受堆积消息
             self.LOG.info("处理堆积消息中")