Public /register form: username, optional display name, password +
confirm, optional invite token. Submits to POST /api/auth/register
via the new register() helper in auth/store.svelte.ts. On success
the server sets the session cookie and the frontend redirects to /;
on error the page shows a code-specific message (invite_required,
invite_invalid, username_taken, etc.).
Login page gets a "Don't have an account? Register" link below the
form for symmetry.
Tests cover form rendering, password-mismatch client-side rejection,
the happy-path submit + redirect, and the invite-invalid error
mapping.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
bvandeusen
6b23532a61