Mark M2 done in the build-progress section: the public shard widgets over
/public/shard/* (hub + champ/guild/governor/house boards) and the live SSE
feed with self-driven reconnect/backoff (Android-app#7). Update the status
line to "M0–M2 landed; M3 next". No API change — the app consumes the
existing public shard surface.
Co-Authored-By: Claude <noreply@anthropic.com>