Fix viewshed_geo_processing for ArcGIS SDK v300

- Changed QList<Field>() to {} for Field type compatibility
- Updated signal connection from jobStatusChanged to statusChanged
- Changed addFeature() to addFeatureAsync() with QFutureWatcher pattern
- Removed ACRGIS_VERSION guards (Qt6/SDK v300 only)
- Added QFutureWatcher<void> m_addFeatureWatcher member to header

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-legatus/Lts/Viewer/SituationMap/MapImpl/viewshed_geo_processing.h

@@ -20,6 +20,7 @@
 #include <QObject>
 #include <QColor>
 #include <QPointF>
+#include <QFutureWatcher>
 
 // forward:
 namespace Esri
@@ -79,9 +80,7 @@ public:
 
 protected slots:
   void onJobStatusChanged();
-#if ACRGIS_VERSION >= 0x640E00 // 100.14.0
   void onJobStatusChangedWithJsParameter(const Esri::ArcGISRuntime::JobStatus &);
-#endif // ACRGIS_VERSION
 
   void onErrorOccuredGeoprocessingTask(const Esri::ArcGISRuntime::Error &error);
   void onErrorOccuredGeoprocessingJob(const Esri::ArcGISRuntime::Error &error);
@@ -113,6 +112,8 @@ private:
   Esri::ArcGISRuntime::Graphic           *m_originGraphic = nullptr;
   Esri::ArcGISRuntime::Graphic           *m_extentGraphic = nullptr;
 
+  QFutureWatcher<void>                    m_addFeatureWatcher;
+
   LOGGER_T                                m_logger;
 
 }; // class ViewshedGeoProcessing