Three E2E proof tests verify all acceptance criteria through the real server pipeline: player movement, v2 snapshot with visible_tiles, wall hiding (NPC behind wall invisible), corner reveal (move around wall to see NPC). Dynamic test snapshot tracks player position from queued inputs with simple LOS and Manhattan-distance visibility for standalone demo mode. 88 client + 112 server tests passing. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>