fix: fight restart bug, mobile TTS, character sizing, bitcoin symbols

- Fix fight replay showing empty scene: validate rounds before playing,
  retry loading fight data up to 5 times when rounds are missing
- Add COOP/COEP headers to production server for SharedArrayBuffer
  (required by Kokoro TTS WASM threading on mobile)
- Add blob: to scriptSrc/workerSrc CSP for Web Worker support
- Fix mobile character cutoff: raise ground line to 0.82, add
  MOBILE_SCALE_CAP (0.55) so fighters never shrink too small
- Add ₿ bitcoin chest badge to all fighter sprites (scales with tier)
- Add sats coin stack on bot profile page proportional to satsWon
- Seed dev tournament with 8 mock bots on startup (dev mode only)

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

server/src/engine/dev-seed.ts

@@ -0,0 +1,54 @@
+import { db, schema } from '../db/index.js'
+import { sql } from 'drizzle-orm'
+import { createTournament, joinTournament, startTournament } from './tournaments.js'
+import { logger } from '../lib/logger.js'
+
+/** Seed a dev tournament with mock bots for testing betting/tournament UI */
+export async function seedDevTournament(): Promise<void> {
+  // Skip if a tournament already exists
+  const existing = db.select({ count: sql<number>`count(*)` })
+    .from(schema.tournaments)
+    .get()
+  if (existing && existing.count > 0) {
+    logger.info('dev-seed', 'tournaments already exist — skipping seed')
+    return
+  }
+
+  // Grab 8 mock bots for the tournament
+  const bots = db.select({ id: schema.bots.id, name: schema.bots.name })
+    .from(schema.bots)
+    .limit(8)
+    .all()
+
+  if (bots.length < 4) {
+    logger.warn('dev-seed', `only ${bots.length} bots — need at least 4 for tournament seed`)
+    return
+  }
+
+  // Create tournament
+  const tournamentId = createTournament(
+    'SATOSHI SHOWDOWN #1',
+    'single_elim',
+    8,
+    100,
+  )
+
+  // Join bots
+  for (const bot of bots.slice(0, 8)) {
+    try {
+      joinTournament(tournamentId, bot.id)
+    } catch (err) {
+      logger.warn('dev-seed', `failed to join bot ${bot.name}: ${(err as Error).message}`)
+    }
+  }
+
+  // Start the tournament (seeds by elo, generates bracket)
+  try {
+    startTournament(tournamentId)
+    logger.info('dev-seed', `seeded tournament "${tournamentId}" with ${Math.min(bots.length, 8)} bots`)
+  } catch (err) {
+    logger.warn('dev-seed', `failed to start tournament: ${(err as Error).message}`)
+  }
+
+  logger.info('dev-seed', 'dev seeding complete — tournament ready for testing')
+}