Create a contributor recognition workflow #34
Description
Summary
Contributors should get recognition somewhere more visible than the merged PR list. The repo now has a CONTRIBUTORS.md file, but the maintainer workflow for keeping it current should stay lightweight.
Acceptance Criteria
- Keep CONTRIBUTORS.md updated when first-time contributors land a PR.
- Use the PR template to collect preferred display name and public link.
- Document the recognition flow in CONTRIBUTING.md.
- Keep the contributor list easy to maintain by hand.