Implement mainwindow example

Sine Striker

2023-12-05 f8975a7d449bac21a2fdbc1a8ca85d1f5b99b362

 examples/mainwindow/mainwindow.h

@@ -7,6 +7,9 @@
public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

protected:
    void installWindowAgent();
};

#endif // MAINWINDOW_H