/* auth.jsx
*
* Dedicated-route auth UI (no modal). Three exported components:
*
* — top-right TopBar button. "Sign in" link when
* logged out, user menu when logged in.
* — full-page login form. Email + Password.
* — full-page signup form. Full Name + Email +
* Password + Confirm Password. No username
* (auto-generated server-side from email).
* — interstitial for gated tabs; provides a
* "Go to sign in" button.
*
* Why no modal: browser password managers (Firefox, Chrome, Safari) all
* have poor autofill heuristics for dynamically-rendered modal forms.
* Dedicated routes with proper