- Add SSE human_challenge listener for instant input activation with auto-focus - Buffer challenges during 3s round cooldown, apply with correct remaining time - Map 'human' archetype to fighter-looking archetypes (boxer, ninja, etc.) in sprite system - Show challenge questions in battle log via round_start SSE events - Ensure human players are always botA (left side) in queue matchmaking Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>