/**
 * 🏅 SKILL-BASED WINNER SELECTION
 * Cryptographically secure
 */
private generateRandomSeed(): string {
  // 32 bytes = 256 bits of entropy
  const randomBytes = crypto.randomBytes(32);
  return randomBytes.toString('hex');
}

private selectRandomIndex(total, seed) {
  // SHA-256 hash of seed
  const hash = crypto.createHash('sha256')
    .update(seed).digest();
  const randomValue = hash.readBigUInt64BE(0);
  const index = Number(randomValue % BigInt(total));
  return index;
}