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/tree_view.cpp

@@ -0,0 +1,82 @@
+/**
+ * @RDE_HEADER@
+ * A QTreeView with some events catched
+ * $Id$
+ * $HeadURL$
+ * $Author$
+ *
+ * Created by Mike Wille, SLSE, 2016-10-07
+ */
+
+#include "tree_view.h"
+
+#include <QGuiApplication>
+#include <QKeyEvent>
+
+namespace LtsDataView
+{
+
+// needed until QTBUG-78726 is fixed
+void TreeView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight,
+                           const QVector<int> &roles)
+{
+  QTreeView::dataChanged(topLeft, bottomRight, roles);
+  if (!m_toolTipPos.isNull() && (roles.isEmpty() || roles.contains(Qt::ToolTipRole)))
+  {
+    if (viewport()->mapToGlobal(m_toolTipPos) != QCursor::pos())
+    {
+      m_toolTipPos = QPoint();
+      return;
+    }
+    const QModelIndex index = indexAt(m_toolTipPos);
+    if (index.row() >= topLeft.row() && index.row() <= bottomRight.row() &&
+        index.column() >= topLeft.column() && index.column() <= bottomRight.column())
+    {
+
+      QHelpEvent he(QEvent::ToolTip, m_toolTipPos, viewport()->mapToGlobal(m_toolTipPos));
+      QTreeView::viewportEvent(&he);
+      m_toolTipPos = QPoint();
+    }
+  }
+}
+
+void TreeView::keyPressEvent(QKeyEvent *event)
+{
+  if (QGuiApplication::keyboardModifiers() == Qt::ControlModifier
+      && event->key() == Qt::Key_C)
+    emit signalCopyToClipBoard(); // queue !
+
+  QTreeView::keyPressEvent(event);
+}
+
+bool TreeView::edit(const QModelIndex &index, EditTrigger trigger, QEvent *event)
+{
+
+  if (trigger == QAbstractItemView::NoEditTriggers)
+  {
+    const QMouseEvent *me = dynamic_cast<QMouseEvent*>(event);
+    if (me && me->buttons().testFlag(Qt::LeftButton))
+      trigger = QAbstractItemView::AllEditTriggers;
+  }
+  return QTreeView::edit(index, trigger, event);
+}
+
+// needed until QTBUG-78726 is fixed
+bool TreeView::viewportEvent(QEvent *event)
+{
+  bool ret = QTreeView::viewportEvent(event);
+  if (event->type() == QEvent::ToolTip)
+  {
+    if (!ret)
+    {
+      QHelpEvent *he = static_cast<QHelpEvent*>(event);
+      m_toolTipPos = he->pos();
+    }
+    else
+      m_toolTipPos = QPoint();
+  }
+  return ret;
+}
+
+
+} // namespace LtsDataView