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/Common/LtsSession/lts_session_data.cpp

@@ -24,7 +24,7 @@ LtsSessionData::LtsSessionData()
   , m_isTablet(false)
   , m_placeScriptScreens(false)
 {
-  
+  //setAsTablet(true); // IMPORTANT: if you want to set this to true for testing, you have to set TABLET_MODE cmake flag to true, otherwise this will crash
   setAsTablet(false);
 
   clear();
@@ -50,9 +50,9 @@ void LtsSessionData::loggedOut()
 
 void LtsSessionData::removePresets()
 {
-  
+  //m_domainIdPreset = -1;  keep domain ID !
   m_partitionIdPreset = -1;
-  m_partitionTypePreset = IDL::PartitionType::Any; 
+  m_partitionTypePreset = IDL::PartitionType::Any; // FIXME: make invalid !?
 
   m_operatorNamePreset.clear();
   m_passwordPreset.clear();
@@ -101,7 +101,7 @@ const QVector<int> LtsSessionData::getVisibleParties(int exerciseId) const
 void LtsSessionData::setAsTablet(bool isTablet)
 {
   m_isTablet = isTablet;
-  
+  //m_debugFlags.insert(QStringLiteral("isTablet"), isTablet);
 }
 
-} 
+} // namespace LtsSessionData