refactor(api): Fix issues reported by pre-commit

- Modified code layout and formatting in multiple files, improving code readability.
  - Updated import statements, removing unused libraries.
  - Simplified the writing of some functions and exception handling.

lightrag/api/requirements.txt

@@ -1,20 +1,20 @@
 aiofiles
 ascii_colors
+asyncpg
+distro
 fastapi
+httpcore
+httpx
+jiter
 numpy
+openai
+passlib[bcrypt]
 pipmaster
+PyJWT
 python-dotenv
+python-jose[cryptography]
 python-multipart
+pytz
 tenacity
 tiktoken
 uvicorn
-jiter
-httpcore
-distro
-httpx
-openai
-asyncpg
-pytz
-python-jose[cryptography]
-passlib[bcrypt]
-PyJWT