Authentication
Google sign-in in the free version, magic link and email in Pro.
There is no password anywhere in this starter. The free version signs people in with Google: set GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET (see Google OAuth) and the button appears on /login and /register.
Email sign-in
Magic-link sign-in and the transactional emails behind it (invitations, receipts, delivery log) ship with Pro. The email field on the login page is a disabled preview, and the free server registers no email sign-in endpoint, so it can't be switched on from the browser.