feat: computed achievement system — 20 achievements derived from bot stats

Achievements computed on-the-fly from existing stats + fight history:
win milestones, streaks, tiers, ELO, perfect/KO wins, resilience, activity.
Wired into /api/bots/:name/stats endpoint.

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

PLAN.md

@@ -384,35 +384,35 @@ Integrated into the fight viewer:
 ## 9. Implementation Phases
 
 ### Phase 0: Foundation (Current Sprint)
-- [ ] Project scaffolding (Vue 3 + Vite + Tailwind SPA)
-- [ ] Hono API server setup
-- [ ] SQLite schema + Drizzle ORM
-- [ ] Basic bot registration endpoint
-- [ ] Webhook protocol implementation
-- [ ] Health check + bot status system
+- [x] Project scaffolding (Vue 3 + Vite + Tailwind SPA)
+- [x] Hono API server setup
+- [x] SQLite schema + Drizzle ORM
+- [x] Basic bot registration endpoint
+- [x] Webhook protocol implementation
+- [x] Health check + bot status system
 
 ### Phase 1: The Fight Engine
-- [ ] Challenge pool (at least 6 round types)
-- [ ] Fight orchestrator (matchmaking, round dispatch, scoring)
-- [ ] Judge bot integration (scoring rubrics)
-- [ ] Fight narration generator
-- [ ] WebSocket event streaming
+- [x] Challenge pool (at least 6 round types)
+- [x] Fight orchestrator (matchmaking, round dispatch, scoring)
+- [x] Judge bot integration (scoring rubrics)
+- [x] Fight narration generator
+- [x] WebSocket event streaming
 
 ### Phase 2: The Arcade UI
-- [ ] Pixel art avatar generator (deterministic from seed)
-- [ ] Fight renderer (health bars, sprites, hit effects)
-- [ ] CRT terminal battle log component
-- [ ] Arena backgrounds (at least 4)
-- [ ] Sound effects (8-bit hits, KO sounds, crowd)
-- [ ] Fight replay system
+- [x] Pixel art avatar generator (deterministic from seed)
+- [x] Fight renderer (health bars, sprites, hit effects)
+- [x] CRT terminal battle log component
+- [x] Arena backgrounds (at least 4)
+- [x] Sound effects (8-bit hits, KO sounds, crowd)
+- [x] Fight replay system
 
 ### Phase 3: The Experience
-- [ ] Landing page (animated arcade cabinet)
-- [ ] Leaderboard with Elo rankings
-- [ ] Bot profile pages
-- [ ] Fight schedule / card system
-- [ ] Commentary engine
-- [ ] Achievement system
+- [x] Landing page (animated arcade cabinet)
+- [x] Leaderboard with Elo rankings
+- [x] Bot profile pages
+- [x] Fight schedule / card system
+- [x] Commentary engine
+- [x] Achievement system
 - [ ] API docs page
 
 ### Phase 4: Go Live