Leave match results with the Menu key, as browsers keep Escape

The results prompt shows the Menu key instead of Esc, which a browser
uses to leave fullscreen. Escape still works on desktop.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/main.cpp

@@ -57,8 +57,8 @@ void game_tick(Game& game)
     Input& input = game.input;
     match.isOnline = game.session.isActive;
     match.isPlayRequested = input.isPlayRequested;
-    match.isSandboxRequested = !game.menu.isOpen && !game.menu.isEscapeTaken &&
-                               (input.is_pressed(SDL_SCANCODE_ESCAPE) || input.is_pad_tapped(SDL_GAMEPAD_BUTTON_EAST));
+    match.isSandboxRequested =
+        game.menu.isLeaving || (!game.menu.isOpen && input.is_pad_tapped(SDL_GAMEPAD_BUTTON_EAST));
     match.colorWanted = game.settings.color_get();
     game.sim.tick();
     input.tick_end();