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/OcSituationServer/handler_oc_data.cpp

@@ -605,7 +605,7 @@ void HandlerOcData::handleEquipmentRegistration(const QByteArray &data)
 
   ParticipantManagement::Participant part = m_ppmDtc->participant(participantId);
 
-  if (part.equipmentNumber.is_set() && equipmentNumber > 0)
+  if (part.equipmentNumber.has_value() && equipmentNumber > 0)
   {
     // we need a deregistration first!
     ParticipantManagement::RegisterParticipantRequest dereq;