A Gitea pull mirror replicates commits and tags only, so the mirror's Releases
page shows bare tags with nothing to download. ClassicAPI's mirror-release
workflow pushes the notes and attachments over through Gitea's API; this is
that workflow pointed at brues/TwitchEmotes.
Manual only: workflow_call is dropped, so a release does not trigger it and
nothing else calls it. Run it from the Actions UI with a tag, or with the tag
blank to backfill every release.
Needs its own MIRROR_TOKEN secret on this repo before the first run.