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/pages/LeaderboardPage.vue

@@ -28,7 +28,7 @@ onMounted(async () => {
   isLoading.value = false
 })
 
-const tierName = (t: number) => ['UNRANKED', 'ROOKIE', 'RISING', 'CONTENDER', 'CHAMPION', 'LEGEND'][t] || '???'
+const tierName = (t: number) => ['BABY', 'BRONZE', 'SILVER', 'GOLD', 'PLATINUM', 'DIAMOND', 'LEGEND'][t] || '???'
 const tierClass = (t: number) => `tier-${t}`
 const record = (b: Bot) => `${b.wins}W - ${b.losses}L`
 </script>