How This Prototype Connects To Supabase

This flow uses Supabase Auth to create users, confirm email, sign in, and manage account settings.

1. 1. Create account: the form sends email + password to Supabase (`/auth/v1/signup`).
2. 2. Email confirmation: Supabase sends a confirmation email to the user.
3. 3. Sign in: after confirmation, sign-in uses Supabase password auth (`/auth/v1/token?grant_type=password`).
4. 4. Session storage: access and refresh tokens are stored locally in the browser for this prototype.
5. 5. User profile: user info is fetched from Supabase (`/auth/v1/user`) and shown in User Preferences.
6. 6. Update profile/password: changes are saved back to Supabase via `PUT /auth/v1/user`.