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/Services/CentralEffectSimulation/Plugins/Ces2D/plugin.cpp

@@ -40,7 +40,7 @@ Ces2DInterfaceImpl::Ces2DInterfaceImpl(CentralEffectSimulation::Plugin::DataProv
   , m_db(db)
   , m_handlerBuildingData(handlerBuildingData)
   , m_handlerParticipant(handlerParticipant)
-  , m_logger(NGL::NGLLoggerBootstrap::getNGLRootLogger().getNGLLogger("CES.Plugin.CentralEffectSimulation2DInterfaceImpl"))
+  .getNGLLogger("CES.Plugin.CentralEffectSimulation2DInterfaceImpl"))
 {
   Q_UNUSED(settings)
 }