Advance KDE Plasma and Qt integration

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

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

local/recipes/wayland/qt6-wayland-smoke/source/main.cpp

@@ -1,11 +1,51 @@
 #include <QByteArray>
 #include <QCoreApplication>
 #include <QGuiApplication>
+#include <QWindow>
+#include <QBackingStore>
+#include <QPainter>
 #include <QDebug>
 #include <QTimer>
 
 #include <cstdio>
 
+class ColoredWindow : public QWindow {
+public:
+    ColoredWindow() : QWindow(), m_backingStore(this) {
+        resize(320, 240);
+    }
+
+    void exposeEvent(QExposeEvent *) override {
+        if (!isExposed())
+            return;
+        render();
+    }
+
+    void resizeEvent(QResizeEvent *) override {
+        m_backingStore.resize(size());
+        if (isExposed())
+            render();
+    }
+
+    void render() {
+        QRect rect(0, 0, width(), height());
+        m_backingStore.beginPaint(rect);
+        QPaintDevice *device = m_backingStore.paintDevice();
+        if (device) {
+            QPainter p(device);
+            p.fillRect(rect, QColor(180, 30, 30));
+            p.setPen(Qt::white);
+            p.drawText(rect, Qt::AlignCenter,
+                QStringLiteral("Red Bear OS\nQt6 Wayland Smoke Test"));
+        }
+        m_backingStore.endPaint();
+        m_backingStore.flush(rect);
+    }
+
+private:
+    QBackingStore m_backingStore;
+};
+
 int main(int argc, char **argv) {
     const QByteArray platform = qEnvironmentVariableIsSet("QT_QPA_PLATFORM")
             ? qgetenv("QT_QPA_PLATFORM")
@@ -19,6 +59,12 @@ int main(int argc, char **argv) {
 
     qInfo() << "qt6-wayland-smoke platform" << QGuiApplication::platformName();
 
-    QTimer::singleShot(1000, &app, &QCoreApplication::quit);
+    ColoredWindow window;
+    window.setTitle(QStringLiteral("Red Bear OS - Qt6 Wayland Smoke"));
+    window.show();
+    std::fprintf(stderr, "qt6-wayland-smoke window shown, %dx%d\n",
+                 window.width(), window.height());
+
+    QTimer::singleShot(3000, &app, &QCoreApplication::quit);
     return app.exec();
 }