pip package & publishing to PYPI

[Bomme]

Packaging and CI setup for the project, transitioning from setup.py to a PEP 621-compliant pyproject.toml, using uv as front-end and hatchling as build backend.

Packaging and Publishing Improvements:

• Added a pyproject.toml file with project metadata, dependencies, build system configuration, and support for Python 3.7–3.13, enabling modern packaging standards and future PyPI publishing.
• Removed the legacy setup.py file, fully switching to the new build system.
• Added a GitHub Actions workflow (.github/workflows/publish.yml) for automated building and publishing of releases to PyPI.

Continuous Integration Updates:

• Updated the smoke test workflow to use a matrix strategy for Python 3.7–3.13, replaced pip with uv for dependency management and running tests, and improved reliability with fail-fast.
• Added .python-version file specifying Python 3.13 for local development environment consistency.