USER_GUIDE.md at the repo root is the single source of truth --
frontend/public/USER_GUIDE.md symlinks to it so the same file is both
readable directly in the repo and served by the app, rendered on a new
/help page reusing the existing markdown renderer. Scoped to regular
member features (messaging, rooms, attachments, notifications,
profile); room admin/site admin features are intentionally left out.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
