QDS-11412 Implement built-in QR code reader

This MR brings the following features;

• add: built-in QR code reader based on zxing-cpp library
• chore: bump to Qt 6.6.1 to fix camera access issues (QTBUG-116526)

src/backend.cpp

@@ -26,13 +26,15 @@
 #include "backend.h"
 #include "qapplication.h"
 
+#include <QCameraDevice>
 #include <QDesktopServices>
 #include <QFileInfo>
 #include <QJsonArray>
 #include <QJsonObject>
-
+#include <QMediaDevices>
 #include <QSettings>
 #include <QSslSocket>
+#include <QVideoSink>
 
 Backend::Backend(QObject *parent)
     : QObject(parent)
@@ -76,6 +78,38 @@ void Backend::initialize()
     // Check if updateInBackground is enabled
     updateInBackground(settings.value("system/updateInBackground").toBool());
     qDebug() << "Initialization complete";
+
+    m_camera = new QCamera(QMediaDevices::videoInputs().at(0));
+
+    for (const QCameraFormat &fmt : QMediaDevices::videoInputs().at(0).videoFormats()) {
+        qDebug() << "======================";
+        qDebug() << "max framerate:" << fmt.maxFrameRate();
+        qDebug() << "min framerate:" << fmt.minFrameRate();
+        qDebug() << "pix fmt:" << fmt.pixelFormat();
+        qDebug() << "res:" << fmt.resolution();
+    }
+    m_imageCapture = new QImageCapture;
+
+    m_camera->setFocusMode(QCamera::FocusModeAuto);
+
+    m_captureSession.setCamera(m_camera);
+
+    m_captureSession.setVideoOutput(&m_videoWidget);
+    m_captureSession.videoSink();
+    m_captureSession.setImageCapture(m_imageCapture);
+
+    connect(m_captureSession.videoSink(),
+            &QVideoSink::videoFrameChanged,
+            this,
+            [&](const QVideoFrame &frame) {
+                qDebug() << "Video frame changed";
+                QImage image = frame.toImage();
+                qDebug() << "Image captured";
+            });
+    // m_videoWidget.show();
+    // m_camera->start();
+    //on shutter button pressed
+    // m_imageCapture->capture();
 }
 
 void Backend::updateInBackground(const bool &enabled)