🚀 Feature: Add web-ext builder Block for browser extensions

[JoshuaKGoldberg]

Feature Request Checklist

• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Overview

For projects of mine such as https://github.com/JoshuaKGoldberg/refined-saved-replies, I'd like to be able to stick with CTA fully. But that means swapping out the default tsup builder Block for a web-ext one.

Additional Info

🎁

[github-actions]

🎉 This is included in version v2.28.0 🎉

The release is available on:

• GitHub releases
• npm package (@latest dist-tag)

Cheers! 📦🚀