Preview task-group selections until Meta is released

plasma-task-group-shortcuts/windowpreview.h

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <QModelIndex>
+#include <QQmlEngine>
+#include <QQuickWindow>
+#include <memory>
+
+class WindowPreview
+{
+public:
+    WindowPreview();
+    void show(const QModelIndex &task, int panelLocation);
+    void setAnchor(const QRect &button);
+    void hide();
+
+private:
+    QQmlEngine m_engine;
+    std::unique_ptr<QQuickWindow> m_window;
+    int m_panelLocation = 0;
+};