BUILD_RTI conditional fixes and Qt6 API updates

- cmake/FindRTI.cmake: Add INTERFACE placeholder targets when RTI not found
- cmake/FindRTI.cmake: Force BUILD_RTI=OFF when RTI not installed
- Lts/Common/LtsSession/CMakeLists.txt: Make LtsSessionDataDds conditional on BUILD_RTI
- Lts/Viewer/CMakeLists.txt: Make LtsDataView conditional on BUILD_RTI
- Lts/Plugins/*/CMakeLists.txt: 97 plugin files wrapped in BUILD_RTI conditionals
- cmake/NGLMacros.cmake: Fix NGL_ADD_BIG_RESOURCES macro (removed premature return())
- Multiple Qt6 API fixes: QLinkedList→std::list, QStringRef→QStringView, etc.
- BUILD_RTI_FIXES_SUMMARY.md: Comprehensive documentation of all fixes

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

qt6-after/qt6-migrated-legatus/Lts/Viewer/LtsDataView/lts_columns_setting.h

@@ -0,0 +1,84 @@
+/**
+  * @RDE_HEADER@
+  * LtsColumnsSetting Organise table columns
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Steve Kemayou, ESZS, 2025-03-19
+  */
+
+#pragma once
+
+#include <LtsDataView/lts_data_view_export.h>
+
+#include "LtsWidgets/lts_frameless_dialog.h"
+
+#include <QWidget>
+#include <QDialog>
+#include <QAbstractTableModel>
+
+namespace Ui {
+class LtsColumnsSetting;
+}
+namespace LtsDataView
+{
+struct  ColumnOrganiserInfo
+{
+  int logicalIndex;       // logicalIndex
+  QString name;
+  bool show;
+  bool debugOnly = false; // column is only displayed in debug mode
+  bool hide() const {return !show;}
+};
+
+class ColumnOrganiserModel;
+
+class LTSDATAVIEW_EXPORT LtsColumnsSettingWidget : public  LtsWidgets::LtsFramelessDialog
+{
+  Q_OBJECT
+
+public:
+  explicit LtsColumnsSettingWidget(const QVector<ColumnOrganiserInfo> &columnInfoVec, QWidget *parent = nullptr);
+  ~LtsColumnsSettingWidget();
+
+signals:
+  void columnVisibilityChanged(const QVector<ColumnOrganiserInfo> &data);
+  void columnsResetted();
+
+private slots:
+  void onResetClicked();
+  void onApplyClicked();
+  void onAbortClicked();
+
+
+private:
+  Ui::LtsColumnsSetting *m_ui;
+
+  ColumnOrganiserModel *m_model;
+};
+
+class ColumnOrganiserModel final : public QAbstractTableModel
+{
+  Q_OBJECT
+public:
+  explicit ColumnOrganiserModel(QObject *parent = nullptr);
+  ~ ColumnOrganiserModel(){}
+
+  void setModelData(const QVector<ColumnOrganiserInfo> &infos);
+protected:
+  void insertRow(const ColumnOrganiserInfo &info);
+  int columnCount(const QModelIndex &parent = QModelIndex())const override;
+  int rowCount(const QModelIndex &parent = QModelIndex() ) const override;
+  QVariant data (const QModelIndex &index, int role = Qt::DisplayRole)const override;
+  bool setData(const QModelIndex &index, const QVariant &value, int role) override;
+  Qt::ItemFlags flags(const QModelIndex &index) const override;
+  QVariant headerData(int section, Qt::Orientation orientation, int role) const override final;
+
+private:
+
+  QVector<ColumnOrganiserInfo> m_vecData;
+};
+
+} // namespace LtsDataView
+
+Q_DECLARE_METATYPE(LtsDataView::ColumnOrganiserInfo)