ci: add GitHub Actions for matrix testing and PyPI releases

[SergeiNikolenko]

Summary

• add CI workflows for Ruff, package smoke checks, and pytest across Python 3.11-3.13
• add release workflows for automatic PyPI publishing on successful main CI and a manual publish fallback
• publish to PyPI via repository secret PYPI_API_TOKEN
• add package metadata for PyPI and keep pyproject.toml version aligned with matcha/__version__.py
• drop unused hydra-core from direct runtime dependencies
• document the CI/CD design in docs/superpowers/specs/2026-03-30-matcha-ci-cd-design.md

Notes

• I re-checked Python 3.10 while continuing this branch; it is still not viable for the published package because numpy>=2.3.5 currently requires Python >=3.11
• GitHub environment pypi has been created in LigandPro/Matcha
• PyPI publishing now uses the environment secret PYPI_API_TOKEN

Local checks

• uv sync --extra test
• uv run python -c "import matcha; from matcha.__version__ import __version__; print(__version__)"
• uv run matcha --help
• uv run pytest tests/test_multigpu_cmd_build.py -q
• uv build
• uvx twine check dist/*
• workflow YAML parse check