- user_block, user_unblock and admin_email_otp changed state on GET, so an
<img> tag could lock a user out or trigger OTP emails through an
admin's session. They now require POST; the buttons are CSRF forms.
- The console token cookie is set with httponly, SameSite=Lax and, on
HTTPS, secure. Only novncd reads it; the page gets the token directly.
