- /api/internal/grant: secret-auth endpoint for payment-router to
provision access on a paid order — find-or-create user (emailVerified,
temp password, mustChangePassword), enroll by course slug list,
AccessLog, delivery email. Idempotent by order_id.
- User.mustChangePassword flag (+ migration); (student) layout redirects
flagged users to /change-password (forced first-login change).
- email.ts: sendCourseGrantEmail (temp password for new buyers).
- middleware: /api/internal is public (own secret auth).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>