修改引用逻辑，修改长期记忆bug

app/backend.py

@@ -16,7 +16,7 @@ from pydantic import BaseModel
 from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver
 from app.agent import AIAgentService
 from app.history import ThreadHistoryService
-from app.logger import debug, info, warning, error
+from app.logger import info, error
 
 # 加载 .env 文件
 load_dotenv()
@@ -28,7 +28,6 @@ DB_URI = os.getenv(
     "postgresql://postgres:huang1998@ai-postgres:5432/langgraph_db?sslmode=disable"
 )
 
-
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """应用生命周期管理：创建并注入全局服务"""
@@ -53,7 +52,6 @@ async def lifespan(app: FastAPI):
         # 5. 关闭时自动清理数据库连接（async with 负责）
         info("🛑 应用关闭，数据库连接池已释放")
 
-
 app = FastAPI(lifespan=lifespan)
 
 # CORS 中间件（允许前端跨域）
@@ -65,14 +63,12 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
-
 # ========== 健康检查端点 ==========
 @app.get("/health")
 async def health_check():
     """健康检查端点，用于 Docker 和 CI/CD 监控"""
     return {"status": "ok", "service": "ai-agent-backend"}
 
-
 # ========== Pydantic 模型 ==========
 class ChatRequest(BaseModel):
     message: str
@@ -80,7 +76,6 @@ class ChatRequest(BaseModel):
     model: str = "zhipu"
     user_id: str = "default_user"
 
-
 class ChatResponse(BaseModel):
     reply: str
     thread_id: str
@@ -90,18 +85,15 @@ class ChatResponse(BaseModel):
     total_tokens: int = 0
     elapsed_time: float = 0.0
 
-
 # ========== 依赖注入函数 ==========
 def get_agent_service(request: Request) -> AIAgentService:
     """从 app.state 中获取全局 AIAgentService 实例"""
     return request.app.state.agent_service
 
-
 def get_history_service(request: Request) -> ThreadHistoryService:
     """从 app.state 中获取全局 ThreadHistoryService 实例"""
     return request.app.state.history_service
 
-
 # ========== HTTP 端点 ==========
 @app.post("/chat", response_model=ChatResponse)
 async def chat_endpoint(
@@ -135,7 +127,6 @@ async def chat_endpoint(
         elapsed_time=elapsed_time
     )
 
-
 # ========== 历史查询接口 ==========
 @app.get("/threads")
 async def list_threads(
@@ -147,7 +138,6 @@ async def list_threads(
     threads = await history_service.get_user_threads(user_id, limit)
     return {"threads": threads}
 
-
 @app.get("/thread/{thread_id}/messages")
 async def get_thread_messages(
     thread_id: str,
@@ -158,7 +148,6 @@ async def get_thread_messages(
     messages = await history_service.get_thread_messages(thread_id)
     return {"messages": messages}
 
-
 @app.get("/thread/{thread_id}/summary")
 async def get_thread_summary(
     thread_id: str,
@@ -169,7 +158,6 @@ async def get_thread_summary(
     summary = await history_service.get_thread_summary(thread_id)
     return summary
 
-
 # ========== 流式对话接口 ==========
 @app.post("/chat/stream")
 async def chat_stream_endpoint(
@@ -204,7 +192,6 @@ async def chat_stream_endpoint(
         }
     )
 
-
 # ========== WebSocket 端点（可选） ==========
 @app.websocket("/ws")
 async def websocket_endpoint(
@@ -228,7 +215,6 @@ async def websocket_endpoint(
     except WebSocketDisconnect:
         pass
 
-
 if __name__ == "__main__":
     import uvicorn
     # 使用环境变量或默认端口 8079（避免与 llama.cpp 的 8081 端口冲突）