Account app: sign-in, MFA, sessions, email flows, and subscription management in the portal design.

Vite + React account SPA adopting the Anulum Institute design.
Email verification, password reset, email change with re-verification, and password change end to end.
Active-session list with per-device revocation and sign-out-everywhere.
Polar checkout bound to accounts with tier refresh, self-service deletion, and a recent-activity log.