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>

src/config/__init__.py

@@ -1,12 +1,12 @@
 # Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 # SPDX-License-Identifier: MIT
 
-from .loader import load_yaml_config
-from .tools import SELECTED_SEARCH_ENGINE, SearchEngine
-from .questions import BUILT_IN_QUESTIONS, BUILT_IN_QUESTIONS_ZH_CN
-
 from dotenv import load_dotenv
 
+from .loader import load_yaml_config
+from .questions import BUILT_IN_QUESTIONS, BUILT_IN_QUESTIONS_ZH_CN
+from .tools import SELECTED_SEARCH_ENGINE, SearchEngine
+
 # Load environment variables
 load_dotenv()