New Features

• Email audit: email_log records outgoing mail; admin can search by user / email and view details.
• Verification / reset emails changed to bilingual Chinese-English (Chinese first, English after).
• Email resend gained a cooldown countdown hint.

Experience Improvements

• Unified the site brand name to MathPlotAI, removing old brand wording.
• Updated About-page title and operations copy to match the brand.