修复重构后的导入错误和缺失模块

backend/app/agent/history.py

@@ -4,7 +4,7 @@
 """
 
 from typing import List, Dict, Any
-from ..logger import error # 保持兼容，或者替换为 logger
+from app.logger import error # 保持兼容，或者替换为 logger
 
 class ThreadHistoryService:
     """线程历史查询服务"""

backend/app/agent/service.py

@@ -8,11 +8,12 @@ import asyncio
 
 # 本地模块
 from app.main_graph.graph_builder import GraphBuilder, GraphContext
-from app.main_graph.graph_tools import AVAILABLE_TOOLS, TOOLS_BY_NAME
+from app.main_graph.tools.graph_tools import AVAILABLE_TOOLS, TOOLS_BY_NAME
+from app.main_graph.config import set_stream_writer
 from ..model_services.chat_services import get_all_chat_services, LocalVLLMChatProvider
-from .rag_initializer import init_rag_tool
-from .intent_classifier import get_intent_classifier
-from ..logger import info, warning
+from app.main_graph.utils.rag_initializer import init_rag_tool
+from app.core.intent_classifier import get_intent_classifier
+from app.logger import info, warning
 
 class AIAgentService:
     def __init__(self, checkpointer):