Create CONTRIBUTING.md for project guidelines

Add MIT License to the project

fix: remove obsolete test files

style: format test files with black

chore: add pre-commit hooks for black and ruff

fix: update ruff config to ignore FastAPI patterns (B008)

fix: proper optional hooks with return None, update ruff config

fix: add pass to empty methods instead of noqa

style: format all remaining files

fix: add noqa comment for B027

style: format remaining files with black

fix: resolve remaining ruff linting errors

ci: update workflows to use actions v4

ci: clean up workflows and fix upload-artifact version

style: format code with black and isort