feat: v2 — queue matchmaking, procedural audio, sprite archetypes, auth

- Add queue-based matchmaking with Elo-proximity and 10s timeout
- Procedural sound engine (SFX, voice announcer, 4-track music)
- Sprite system refactored into 6 archetypes (standard, lobster, sheep, cyborg, blob, tank)
- 42+ fight choreographies with themed/generic/wild card selection
- 4 KO finish styles, super-speed mode, hyperdetail close-ups
- Auth routes, JoinBout page, bot profile with stats
- 7-tier ranking system (Baby through Legend)
- Arena and challenge system expansions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/style.css

@@ -180,8 +180,9 @@
 
 /* Tier colors */
 .tier-0 { color: var(--color-text-muted); }
-.tier-1 { color: #8b8b8b; }
-.tier-2 { color: var(--color-neon-cyan); }
-.tier-3 { color: var(--color-neon-purple); }
-.tier-4 { color: var(--color-neon-pink); }
-.tier-5 { color: var(--color-neon-yellow); text-shadow: 0 0 10px rgba(255, 225, 77, 0.5); }
+.tier-1 { color: #cd7f32; }
+.tier-2 { color: #c0c0c0; }
+.tier-3 { color: #ffd700; }
+.tier-4 { color: var(--color-neon-cyan); text-shadow: 0 0 8px rgba(0, 240, 255, 0.3); }
+.tier-5 { color: var(--color-neon-purple); text-shadow: 0 0 10px rgba(184, 61, 255, 0.5); }
+.tier-6 { color: var(--color-neon-pink); text-shadow: 0 0 12px rgba(255, 45, 123, 0.6); }