chore(gitea): regenerate the flat content mirror after the ADR-0020 retrofit

Generated output, not authored content: scripts/sync-plugin-content.sh --all.
Claude Code has no .apm/ awareness, so this compiled mirror must track .apm/ or
the check-plugin-content-sync pre-push hook reports drift.

Deferred to a single commit at the end of the wave on purpose. sync_dir runs
rm -rf before every copy, so running it while seven agents were editing the
same plugin would have raced them; agents were told not to sync for that reason.

Refs #99

plugins/gitea/skills/gitea-releases/references/sources.md

@@ -42,7 +42,6 @@
 - **Research doc:** plugins/gitea/docs/research/docs/gitea/workflow-conventions.md (Release and tag conventions section)
 
 **Contributing files:**
-- SKILL.md (Gotchas — semver tag naming)
-- references/conventions.md
+- references/conventions.md (semver tag naming, release-notes sourcing)
 
 **Status:** `extracted`