Visuals: - isGuestHandle() — handles starting with guest_ or swarm_ are treated as watchers, rendered as translucent gray bodies (alpha 0.35 instead of 0.9) and 1×1 dim minimap dots, so the visual prominence is reserved for people who claimed a real handle. - HUD splits the live count into "players" (named) and "watchers" (anon). tools/ac-arena.mjs — single-file Node CLI for testing the multiplayer loop without a browser. Uses Node 22 native WebSocket so no extra deps. node tools/ac-arena.mjs swarm --count=4 --duration=30 node tools/ac-arena.mjs watch --duration=30 `swarm` opens N WS-only fake players that send arena:hello + arena:cmd at 30Hz with random walk movement; useful for load-testing arena-manager and confirming the server's WS receiveCmd path works (it does — verified 3 clients × 30Hz, both directions, no drops). `watch` is a passive probe that prints arena roster + per-second snap counts; useful as a no-browser sanity check that snaps are flowing. The swarm runs over WS only because Node has no WebRTC. That's actually useful as a diagnostic split — if WS works but the browser still has the drop-cmd problem, the issue is the geckos UDP transport, not the server arena logic.