In Main (no active session) the context-sensitive button now reads "Exit"
and quits the application (stops play mode in the editor), so the player
can leave the build without Alt+F4. Connected behaviour is unchanged:
"Disconnect" leaves the session, "Back to Lobby" ends the match for the
map authority. The button is now interactable whenever idle.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>