Complete Qt6 migration: full clean build green across groups G1-G12 incl. runtime plugin set

new_docker_build.sh gains Group 12 (212 GUI/Data plugins); fixes LtsUtilsGuiDds visibility (LTO-stripped exports), LtsProjectionWorkstation unity name shadow, 6 unity-off dirs (dup file-scope statics, ddsftc INTERFACE sources) and reconfigures BUILD_FILTERMANAGEMENT/BUILD_PLUGINS_SERVICEMONITOR=ON

qt6-after/qt6-migrated-legatus/Lts/Services/OcSituationClient/handler_oc_situation_data.cpp

@@ -301,7 +301,7 @@ bool HandlerOcSituationData::decodeSituationData(const QByteArray &data)
       m_participantData.insert(participantId, participantData);
       DEBUG_LOG(m_logger) << "Adding ParticipantData to internal map: " << participantData;
 
-      if (participantData.equipmentNumber.is_set())
+      if (participantData.equipmentNumber.has_value())
         m_participantId2EqId[participantId] = participantData.equipmentNumber.get();
       else
         m_participantId2EqId[participantId] = 0;  // so the positions can be removed, see e.g. removeAllPositions()