Restore `main` branch
I force-pushed the current production release (https://github.com/mozilla/blurts-server/releases/tag/2025.12.05) to main. This branch contains what used to be in main; we can merge that back in when ready.
Ping me when conflicts are resolved and I'll review
Thanks @kschelonka. I'm not sure how to view just the conflict resolutions in a merge commit, but the conflict was updating the react and react-dom versions in package.json (and thus also in the lockfile), so to resolve that the only change I made in this PR is confirming that we want those at their latest versions. Other than that this contains just the same commits as we had already merged before.