fix ruff

src/mais4u/mais4u_chat/s4u_stream_generator.py

@@ -5,7 +5,6 @@ from src.config.config import global_config
 from src.chat.message_receive.message import MessageRecvS4U
 from src.mais4u.mais4u_chat.s4u_prompt import prompt_builder
 from src.common.logger import get_logger
-from src.person_info.person_info import PersonInfoManager, get_person_info_manager
 import asyncio
 import re