Guard the TOTP verifyKey call behind hasTotp() so a key-only user's null
two_factor_secret never reaches Google2FA::verifyKey(); they reset via a
backup code. Also adds the reset_no_2fa_note lang key (EN + DE) rendered
on the forgot-password form explaining the no-2FA recovery options.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>