fix: Fix pre-commit issues and update tests

- Fix import sorting and unused imports
- Update type annotations to use built-in types (list, dict) instead of typing.List/Dict
- Fix trailing whitespace and end-of-file issues
- Fix Chinese fullwidth comma to regular comma
- Update test_main_cli.py to test_document_rag.py
- Add backward compatibility test for main_cli_example.py
- Pass all pre-commit hooks (ruff, ruff-format, etc.)

examples/main_cli_example.py

@@ -5,7 +5,6 @@ This file is kept for backward compatibility.
 """
 
 import sys
-import os
 
 print("=" * 70)
 print("NOTICE: This script has been replaced!")