修改引用逻辑，修改长期记忆bug

app/nodes/llm_call.py

@@ -3,21 +3,17 @@ LLM 调用节点模块
 负责调用大语言模型并处理响应
 """
 
-import asyncio
 import time
 from typing import Any, Dict
 from langchain_core.language_models import BaseLLM
 from langchain_core.messages import AIMessage
-from langchain_core.runnables import RunnableLambda
-from langgraph.runtime import Runtime
 
 # 本地模块
-from app.graph.state import MessagesState, GraphContext
-from app.prompts import create_system_prompt
-from app.utils.logging import log_state_change, print_llm_input
+from app.graph.state import MessagesState
+from app.agent.prompts import create_system_prompt
+from app.utils.logging import log_state_change
 from app.logger import debug, info, error
 
-
 def create_llm_call_node(llm: BaseLLM, tools: list):
     """
     工厂函数：创建 LLM 调用节点