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/AudioVideoManagement/dds_handler.h

@@ -51,7 +51,7 @@ namespace AudioVideoManagement
 template<class T>
 boost::optional<T> toBoost(const dds::core::optional<T> &optionalValue)
 {
-  if (!optionalValue.is_set())
+  if (!optionalValue.has_value())
     return boost::none;
   return optionalValue.get();
 }