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/loader.py

@@ -2,8 +2,9 @@
 # SPDX-License-Identifier: MIT
 
 import os
+from typing import Any, Dict
+
 import yaml
-from typing import Dict, Any
 
 
 def replace_env_vars(value: str) -> str: