add missing files

launcher/mainmenu.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "uilayer.h"
+
+namespace ui
+{
+class mainmenu_panel : public ui_panel
+{
+  public:
+	mainmenu_panel();
+
+	void render() override;
+};
+} // namespace ui