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/Plugins/PlanEditor/PlanEditorPlugin/Gui/plan_editor_gui_plugin.cpp

@@ -21,12 +21,12 @@
 #include <LtsSession/lts_session_data.h>
 
 
-#include <LtsUtilsGuiDds/request_helper.h>
+#include <LtsUtils/LtsUtilsGui/LtsUtilsGuiDds/request_helper.h>
 
 #include <Plugins/FileManagement/flm_data_plugin_interface.h>
 #include <Plugins/FileManagement/flm_explorer_gui_plugin_interface.h>
 
-#include <Plugins/ParticipantManagement/ppm_data_plugin_interface.h>
+#include <ParticipantManagement/ppm_data_plugin_interface.h>
 
 #include <Plugins/SituationMapPlugin/situation_map_gui_plugin_interface.h>
 

qt6-after/qt6-migrated-legatus/Lts/Plugins/PlanEditor/PlanEditorPlugin/Gui/plan_editor_gui_plugin.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #include <PluginInterfaces/gui_plugin_interface.h>
-#include <Common/ProjectConfig/project_defines.h>
+#include <Lts/Common/ProjectConfig/project_defines.h>
 #include <Plugins/PlanEditor/PlanEditorPlugin/plan_editor_gui_plugin_interface.h>
 #include <Plugins/FileManagement/flm_data_plugin_interface.h>