feat: betting system — Cashu escrow, Lightning deposit/withdraw, payouts

Complete betting infrastructure:
- Bets schema (SQLite) with escrow status tracking
- Cashu token verification + minting (stub for real mint)
- Lightning invoice creation + withdrawal (stub for real LN node)
- Bet placement with odds lock, settlement on fight end
- Payout automation for winners, refunds on draws
- Bet history by pubkey + fight pool info
- Verifiable bet proofs for transparency
- API routes: /api/bets/{odds,place,fight,history,deposit,withdraw}

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

server/src/app.ts

@@ -6,6 +6,7 @@ import { fightsRouter } from './routes/fights.js'
 import { queueRouter } from './routes/queue.js'
 import { authRouter } from './routes/auth.js'
 import { docsRouter } from './routes/docs.js'
+import { betsRouter } from './routes/bets.js'
 import { rateLimit } from './middleware/rate-limit.js'
 
 import { existsSync, readFileSync } from 'fs'
@@ -35,6 +36,7 @@ app.route('/api/bots', botsRouter)
 app.route('/api/fights', fightsRouter)
 app.route('/api/queue', queueRouter)
 app.route('/api/docs', docsRouter)
+app.route('/api/bets', betsRouter)
 
 // In production, serve the frontend SPA
 const __dirname = dirname(fileURLToPath(import.meta.url))