Problem

CI ran tests only on Python 3.14 while pyproject.toml declared support for Python 3.12 and 3.13 as well, so compatibility regressions on those versions could go undetected.

Acceptance Criteria

• CI test workflow runs against Python 3.12, 3.13, and 3.14 via a version matrix
• Coverage artifacts are uploaded per matrix Python version
• pyproject.toml classifiers include Python 3.14 alongside 3.12 and 3.13

Implementation Notes

• Use fail-fast: false so one failing version does not cancel the others
• Job name includes the matrix Python version for easy identification in CI logs
• Artifact names include py{version} to avoid collisions across matrix jobs

References

• .github/workflows/ci-test.yml
• pyproject.toml