Route native close through platform services

src/app_events.cpp

@@ -214,6 +214,11 @@ void App::share_file(std::string path)
     active_platform_services().share_file(path);
 }
 
+void App::request_app_close()
+{
+    active_platform_services().request_app_close();
+}
+
 void App::save_prepared_file(
     std::string path,
     std::string suggested_name,