Improve build workflow and project configuration (#1)

- Run sdist and wheel build jobs on push to main and PRs, not just tag
  pushes. The publish job remains gated on tag pushes.
- Fix cibuildwheel package-dir glob by resolving it in a prior step,
  fixing FileNotFoundError on Windows runners.
- Add descriptive names to all build.yml jobs.
- Remove duplicate version from meson.build (pyproject.toml is the
  single source of truth).
- Add PyPI and OpenSSF Scorecard badges to README.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>