- First visit logs in as a new guest through Keycloak without a form;
the session, including an offline refresh token, is kept in local storage
- Account menu on the home page: guests can log in or sign up, users can
log out (which starts a new guest session)
- The WebSocket client in core authenticates with the access token after
connecting, reports "connected" once the server accepts it, and re-sends
renewed tokens on the open connection
- Game page shows player names; guests appear as "Guest 4F2A"
- Auth channels, AuthUser and player names in UserConnectionInfo move to
core and the backend uses them from there
- Mobile keeps using userKey login for now
