Refactor and improve type hints in MyClass

[bybatkhuu]

This pull request mainly improves code style consistency, updates type annotations for modern Python, and enhances the pre-commit configuration for better code quality enforcement. The most significant changes are grouped below.

Pre-commit configuration improvements:

• Added black and flake8 hooks to .pre-commit-config.yaml for automatic formatting and linting of Python code, including configuration for max line length. [1] [2]
• Refined the exclusion list in .pre-commit-config.yaml to more accurately ignore build, cache, and environment files and directories.

Code style and annotation updates:

• Updated type annotations in src/my_module01/_base.py to use modern Python syntax (e.g., list[float] | None instead of Union[List[float], None]), and improved docstrings to match. [1] [2] [3]
• Standardized comments and section headers in src/my_module01/_base.py for clarity and consistency. [1] [2] [3] [4] [5]

Minor fixes and improvements:

• Improved error messages for value and length checks in the items property setter for better readability. [1] [2]
• Added # noqa: F403,F401 comments to import statements in __init__.py to suppress linting warnings.
• Cleaned up comments in examples/simple/main.py for consistency.