Update the Timeless skin for the existence of "temporary users", a new category of users introduced in the 2022/temp-user topic branch in Gerrit.
I think the only thing to do here is to clean up the personal menu. Currently I see the temporary username prefixed with the message timeless-loggedinas "Logged in as $1", and also a duplicate menu item with ID pt-tmpuserpage. Calling temporary users "logged in" is inconsistent with the general product design in which temporary users are invited to log in or create an account, as if they are not already logged in. So we probably want to say something else there.
