Advance Wayland and KDE package bring-up

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

local/recipes/kde/kf6-kwindowsystem/source/tests/setmainwindowtest.cpp

@@ -0,0 +1,76 @@
+/*
+    This file is part of the KDE libraries
+    SPDX-FileCopyrightText: 2013 Aurélien Gâteau <agateau@kde.org>
+
+    SPDX-License-Identifier: LGPL-2.1-or-later
+*/
+
+#include <kwindowsystem.h>
+
+#include <QApplication>
+#include <QDialog>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QPushButton>
+
+#include "kx11extras.h"
+
+class Window : public QWidget
+{
+public:
+    Window();
+
+private:
+    void showWindow();
+    QLabel *m_label;
+};
+
+Window::Window()
+{
+    QPushButton *button = new QPushButton("Start Test");
+    connect(button, &QPushButton::clicked, this, &Window::showWindow);
+
+    m_label = new QLabel;
+    m_label->setWordWrap(true);
+
+    QVBoxLayout *layout = new QVBoxLayout(this);
+    layout->addWidget(button);
+    layout->addWidget(m_label);
+
+    setMinimumSize(200, 150);
+}
+
+void Window::showWindow()
+{
+    // Wait for user to select another window
+    m_label->setText("Click on another window to show a dialog on it");
+    WId us = winId();
+    while (KX11Extras::activeWindow() == us) {
+        QApplication::processEvents();
+    }
+
+    // Get the id of the selected window
+    WId id = KX11Extras::activeWindow();
+    m_label->setText(QString("Showing dialog on window with id: %1.").arg(id));
+
+    // Create test dialog
+    QDialog *dialog = new QDialog;
+    dialog->setAttribute(Qt::WA_DeleteOnClose, true);
+    QHBoxLayout *layout = new QHBoxLayout(dialog);
+    layout->addWidget(new QLabel("Test Dialog.\nYou should not be able to bring the parent window on top of me."));
+
+    // Show it
+    dialog->setAttribute(Qt::WA_NativeWindow, true);
+    KWindowSystem::setMainWindow(dialog->windowHandle(), id);
+    dialog->exec();
+
+    m_label->setText(QString());
+}
+
+int main(int argc, char **argv)
+{
+    QApplication app(argc, argv);
+    Window window;
+    window.show();
+    return app.exec();
+}