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/CentralEffectSimulation/handler_participant.cpp

@@ -126,7 +126,7 @@ void HandlerParticipant::onParticipantPositionChanged(const ParticipantManagemen
       return;
 
     // [GUEZE-3102] Aufgesessene Teilnehmer bekommen den Schaden vom Fahrzeug, auf dem sie aufgesessen sind.
-    if (data.mountedOn.is_set())
+    if (data.mountedOn.has_value())
       return;
     int floorId = m_handlerBuildingData->getFloorIdFromRoomId(data.roomId);
     int lastFloorId;