1.0.54

Exchange Discord code immediately — skip username prompt

The code is now exchanged with the server right after receiving it,
without asking the user to pick a username first. New accounts use
the Discord display name automatically. Returning players log in
instantly.

Removed the pick-username step and simplified the auth flow.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>