Server-emitted arena:snap packets over UDP were being dropped silently because lib/udp.mjs only listened for tv, fairy:point, and 1v1:move. The server's "prefer UDP, fall back to WS" path sees the emit succeed and never falls back, so arena clients never received snapshots — other players appeared frozen / absent. Same latent bug for squash:move; adding both for consistency. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>