Qt6 Migration: BUILD_RTI Guards, Export-Header und Include-Pfade korrigiert

- BUILD_RTI Guards in LtsSession implementiert (6 Dateien)
- LtsSessionDataDds Stub für BUILD_RTI=OFF erstellt
- Export-Header Stubs erstellt (GuezNasat, AlarmManagement, MarkerManagement)
- Include-Pfade korrigiert (resource_path.h, logger.h, Proxies)
- QStringRef → QString migriert (Qt6 Kompatibilität)
- Qt6::Gui Dependencies hinzugefügt (LtsElevation, AdvancedSymbology)
- FilterManagement-Plugins temporär vom Build ausgeschlossen
- MOC-Probleme gefixt (staticMetaObject, override final)
- Build erfolgreich: 1940 Targets mit BUILD_RTI=OFF im Docker-Container

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

qt6-after/qt6-migrated-legatus/Lts/Plugins/ProjectDataManagement/Gui/PdmComboBox/pdm_combobox.cpp

@@ -221,11 +221,11 @@ bool fill(QComboBox *cbx, PdmComboBoxType type)
     case PdmComboBoxType::CbLanguage:
     {
       const QString languages = LtsUtils::ProjectSettings::getInstance()->value(QStringLiteral("pdm"), QStringLiteral("EquipmentLanguages")).toString();
-      const QVector<QStringRef> slLang = languages.splitRef(QLatin1Char(','));
+      const QStringList slLang = languages.split(QLatin1Char(','));
       QSet<int> alreadySeen;
       alreadySeen += LanguageConfiguration::NoChange;
       cbx->addItem(toString(LanguageConfiguration::NoChange), LanguageConfiguration::NoChange);
-      for (const QStringRef &r : slLang)
+      for (const QString &r : slLang)
       {
         const int langId = r.toInt();
         if (alreadySeen.contains(langId))