feat：接入mongodb

app/main.py

@@ -19,32 +19,37 @@ async def lifespan(application: FastAPI):
     from app.observability.tracing import flush_tracing
     from app.processor.graph import build_graph
     from app.services.agent import AgentService
+    from app.services.persistence import open_persistence
 
-    from app.services.conversation import InMemoryConversationStore
-
-    # TODO 接入 MongoDB 后替换为持久化实现，并同步替换图的 checkpointer
-    store = InMemoryConversationStore()
-    application.state.conversation_store = store
-    application.state.agent_service = AgentService(build_graph(), store)
+    # 按配置选择 MongoDB 或进程内存，会话记录与图检查点使用同一种存储
+    persistence = await open_persistence()
+    application.state.conversation_store = persistence.store
+    application.state.agent_service = AgentService(
+        build_graph(persistence.checkpointer), persistence.store
+    )
     try:
         yield
     finally:
         # 共享客户端只在应用退出时关闭，追踪刷新放到线程避免阻塞事件循环
         try:
-            await close_decision_engine()
+            await persistence.close()
         finally:
             try:
-                await asyncio.to_thread(flush_tracing)
+                await close_decision_engine()
             finally:
-                await logger.complete()
+                try:
+                    await asyncio.to_thread(flush_tracing)
+                finally:
+                    await logger.complete()
 
 
 def create_app() -> FastAPI:
     application = FastAPI(title="Screen Agent API", lifespan=lifespan)
     # 统一处理请求校验、HTTP 错误和未捕获异常
     register_exception_handlers(application)
-    application.include_router(router)
-    application.include_router(conversation_router)
+    # 统一 /api 前缀，方便前端代理和反向代理只配置一条规则
+    application.include_router(router, prefix="/api")
+    application.include_router(conversation_router, prefix="/api")
     return application