fix: kefu.py 补 import re，修复聊天俱乐部过滤接口加载失败

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/views/kefu.py

@@ -3,6 +3,7 @@ import threading
 import traceback
 import uuid
 import hashlib
+import re
 import xmltodict
 import time
 import logging