gui: Add LazyStackedWidget and StackedWidgetProvider interface.

Introduce a generic lazy widget creation pattern for stacked widgets.
StackedWidgetProvider defines createWidget/onShow/onRemove callbacks.
LazyStackedWidget extends MapStackedWidget - when show(key) is called
for a missing key, it delegates to the provider's createWidget to
build and cache the widget on demand.

Signed-off-by: andreidanila1 <andrei.danila@analog.com>

Author: andreidanila1

gui/include/gui/lazystackedwidget.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2026 Analog Devices Inc.
+ *
+ * This file is part of Scopy
+ * (see https://www.github.com/analogdevicesinc/scopy).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef LAZYSTACKEDWIDGET_H
+#define LAZYSTACKEDWIDGET_H
+
+#include "scopy-gui_export.h"
+#include "mapstackedwidget.h"
+#include "stackedwidgetprovider.h"
+
+namespace scopy {
+
+class SCOPY_GUI_EXPORT LazyStackedWidget : public MapStackedWidget
+{
+	Q_OBJECT
+public:
+	explicit LazyStackedWidget(StackedWidgetProvider *provider, QWidget *parent = nullptr);
+	~LazyStackedWidget();
+
+	bool show(QString key) override;
+	bool remove(QString key) override;
+
+private:
+	StackedWidgetProvider *m_provider;
+};
+
+} // namespace scopy
+
+#endif // LAZYSTACKEDWIDGET_H

gui/include/gui/stackedwidgetprovider.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2026 Analog Devices Inc.
+ *
+ * This file is part of Scopy
+ * (see https://www.github.com/analogdevicesinc/scopy).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef STACKEDWIDGETPROVIDER_H
+#define STACKEDWIDGETPROVIDER_H
+
+#include "scopy-gui_export.h"
+
+#include <QString>
+#include <QWidget>
+
+namespace scopy {
+
+class SCOPY_GUI_EXPORT StackedWidgetProvider
+{
+public:
+	virtual ~StackedWidgetProvider() = default;
+
+	virtual QWidget *createWidget(const QString &key) = 0;
+	virtual void onShow(const QString &key, QWidget *widget) = 0;
+	virtual void onRemove(const QString &key, QWidget *widget) = 0;
+};
+
+} // namespace scopy
+
+#endif // STACKEDWIDGETPROVIDER_H

gui/src/lazystackedwidget.cpp

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2026 Analog Devices Inc.
+ *
+ * This file is part of Scopy
+ * (see https://www.github.com/analogdevicesinc/scopy).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "lazystackedwidget.h"
+
+#include <QLoggingCategory>
+
+Q_LOGGING_CATEGORY(CAT_LAZYSTACKEDWIDGET, "LazyStackedWidget")
+
+using namespace scopy;
+
+LazyStackedWidget::LazyStackedWidget(StackedWidgetProvider *provider, QWidget *parent)
+	: MapStackedWidget(parent)
+	, m_provider(provider)
+{}
+
+LazyStackedWidget::~LazyStackedWidget() {}
+
+bool LazyStackedWidget::show(QString key)
+{
+	if(!contains(key) && m_provider) {
+		QWidget *w = m_provider->createWidget(key);
+		if(w) {
+			add(key, w);
+		} else {
+			qWarning(CAT_LAZYSTACKEDWIDGET) << "Provider returned nullptr for key:" << key;
+			return false;
+		}
+	}
+
+	bool result = MapStackedWidget::show(key);
+
+	if(result && m_provider) {
+		m_provider->onShow(key, get(key));
+	}
+
+	return result;
+}
+
+bool LazyStackedWidget::remove(QString key)
+{
+	if(m_provider && contains(key)) {
+		m_provider->onRemove(key, get(key));
+	}
+	return MapStackedWidget::remove(key);
+}
+
+#include "moc_lazystackedwidget.cpp"