Versus map size on the match page; the size sets the number of seats

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

src/main.rs

@@ -358,7 +358,11 @@ fn account_action(a: MenuAction, cloud: &mut Cloud, menu: &mut Menu, app: &mut A
             }
         }
         MenuAction::MatchJoin(code) => app.client.join(&code),
-        MenuAction::MatchCreate => app.client.create_land(&[0, 2, 3, 4], app.settings.map_w, app.settings.map_h, app.settings.difficulty, app.settings.surface, app.settings.events),
+        MenuAction::MatchCreate => {
+            // the map size decides the number of master seats
+            let n = app.settings.match_size;
+            app.client.create_land(lobby::seats_for(n), n, n, app.settings.difficulty, app.settings.surface, app.settings.events)
+        }
         MenuAction::MatchCoopCreate(mission) => {
             let all = campaign::missions();
             if let Some(d) = all.get(mission) {