修复重构后的导入错误和缺失模块

backend/app/main_graph/nodes/memory_trigger.py

@@ -1,8 +1,8 @@
 from typing import Any, Dict
 from langchain_core.runnables.config import RunnableConfig
 from app.main_graph.state import MessagesState
-from ..memory.mem0_client import Mem0Client
-from ..logger import info
+from app.memory.mem0_client import Mem0Client
+from app.logger import info
 
 # 全局变量，在 GraphBuilder 中注入
 _mem0_client: Mem0Client = None