fix: QObjectPrivate::threadData type change when qt >=5.15

iveswang

2024-06-12 7610c3a509b8a04d25e72a6282d9c8ea8ecbd27f

 examples/mainwindow/mainwindow.h

@@ -30,6 +30,8 @@
protected:
    bool event(QEvent *event) override;

    void closeEvent(QCloseEvent *event) override;

private:
    void installWindowAgent();
    void loadStyleSheet(Theme theme);