a692304748
New public register.php flow: email + a GD-rendered math CAPTCHA (no third-party service), a mailed temporary password doubling as email verification, forced password change on first login. Gated behind a new ALLOW_SELF_REGISTRATION toggle (default off). Login moves from username to email (falls back to username for pre-migration accounts without one yet, mirroring qr-vip's existing migration 006 pattern) - self-registration needs email as the identifier. New set_email.php interstitial for legacy accounts. Adds a small PHPMailer-based Mailer class (SMTP, with an unauthenticated-relay option via MAIL_SMTP_AUTH=false) since no mail infrastructure existed in this app before.