feat: 1. replace black with ruff for fomatting and sort import (#489)

2. use tavily from`langchain-tavily` rather than the older one from `langchain-community`

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

tests/test_state.py

@@ -1,8 +1,8 @@
 # Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 # SPDX-License-Identifier: MIT
 
-import sys
 import os
+import sys
 from typing import Annotated
 
 # Import MessagesState directly from langgraph rather than through our application