The login-required popup still rendered a 4-slot OTP (maxLength=4, gated on
length===4) while the main login page already used 6. Users who triggered
login via the dialog saw the old 4-digit code. Match login.tsx: 6 slots,
length===6, same slot sizing.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
