Offer to help maintain Mailcheck

Hi ! We've been actively maintaining a fork of this library at opositatest/mailcheck.

Our fork currently includes:

• Modernized tooling and release automation
• Native ESM, plus CJS and browser builds
• TypeScript types
• CI, security scanning, and automated npm publishing
• Published package: @opositatest/mailcheck

We’d love to help keep this project maintained under the original mailcheck/mailcheck home so the community can benefit from a single, actively maintained package instead of fragmented forks.

If you're open to it, we'd be happy with any arrangement that works for you, for example:

1. Add us as maintainers so we can help with issues, PRs, and releases.
2. If you no longer want to maintain the project directly, discuss transferring the repository.
3. If neither of those is a fit, link to or endorse our fork as the actively maintained successor.

No pressure at all. We mainly wanted to reach out before the ecosystem drifts further across forks.

Thanks again for the original work. We'd be happy to coordinate in whatever way feels most comfortable for you.