Clients now render from the state delivered with each move/update and
drop stale or echoed updates via a ply-version guard, instead of issuing
a full game-state fetch per event. Adds captured-piece trays, a material
advantage badge, a move list, a status line, and the mobile menu toggle.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
