Per-username lockout (5 failed TOTP attempts / 5 min) stops account-targeted
brute force regardless of source IP. Player.totp_secret is now Fernet-
encrypted (ENCRYPTION_KEY env, db/crypto.py) instead of stored in plaintext,
and auth_token is stored as a SHA-256 hash rather than the raw session token.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
