🚀 Feature: Switch footnote annotations to inline

### Feature Request Checklist - [x] I have [searched for related issues](https://github.com/JoshuaKGoldberg/dot-com/issues?q=is%3Aissue) and found none that matched my issue. ### Overview I recently read https://jakearchibald.com/2025/give-footnotes-the-boot and briefly participated in discussion on Bluesky: https://bsky.app/profile/jakearchibald.com/post/3lsvyvpkfo22e. Jake Archibald raises some good points. I think I'd like to switch footnotes to be some kind of inline popover as suggested in https://bsky.app/profile/jakearchibald.com/post/3lt2m6wsmcs2q. ### Additional Info 💖