I've been using playground for a couple of weeks to develop a new website. However, on loading my saved playground today, I find a new admin bar at the bottom in which I can find no way to log in to my test site as "admin" (or as anything). Adding wp-admin or wp-admin.php to the URL does nothing. Loading a saved playground always takes me to an un-logged-in state -- how can I log in using the new UI?