ci: add GitHub workflows

[barvhaim]

Summary

• add CI workflow for lint, tests across Python 3.11-3.13, and package build artifacts
• add release workflow for building distributions and publishing to PyPI on published GitHub releases

Testing

• uv run python -c 'import pathlib, yaml; [yaml.safe_load(p.read_text()) for p in pathlib.Path(".github/workflows").glob("*.yml")]; print("workflow yaml parsed")'
• make build