make demo a GUI application in CMake

Yuhang Zhao

2025-02-10 9e96ea43436d5ed200c57d6b229cddf9bdf9e55a

 src/core/windowitemdelegate.cpp

@@ -17,7 +17,7 @@
    WinIdChangeEventFilter *
        WindowItemDelegate::createWinIdEventFilter(QObject *host,
                                                   AbstractWindowContext *context) const {
        return new WindowWinIdChangeEventFilter(host, context);
        return new WindowWinIdChangeEventFilter(static_cast<QWindow *>(host), context);
    }

}