Implement mainwindow example

Sine Striker

2023-12-05 f8975a7d449bac21a2fdbc1a8ca85d1f5b99b362

 src/quick/quickwindowagent_p.h

@@ -15,7 +15,7 @@
        void init();

        // Host
        QQuickWindow *host{};
        QQuickWindow *hostWindow{};
    };

}