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/GuezMinelayerProcessing/handler_minelayer_data.cpp

@@ -91,7 +91,7 @@ void HandlerMinelayerData::onSpecialSensorDataChanged(const TrainingAreaBase::Sp
   if (data.operationalState != MV_VERLEGEN &&
       data.operationalState != WMV_VERLEGEN)
     return;
-  if (!data.position.is_set())
+  if (!data.position.has_value())
     return;
   {
     // convert TrainingAreaBase::LaneData back to sondersensorik_fahrspur_rt