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/UnitTests/gmp_minefieldInterpreter_test.cpp

@@ -15,7 +15,11 @@
 
 #include <NGLLogger/NGLLoggerBootstrap.h>
 
-Q_DECLARE_METATYPE(wirkfeld_minensperre_rt)
+// wirkfeld_minensperre_rt is already a registered metatype in this TU: the
+// sendeWirkfeld(const wirkfeld_minensperre_rt&, int) signal on ZSSI_WI_Minenfeld_Interpreter
+// auto-registers it via its moc meta-object code (Qt6), so a Q_DECLARE_METATYPE here
+// would be a redefinition of the already-instantiated QMetaTypeId specialization.
+// (Qt5 tolerated the duplicate; Qt6 rejects it.) Keep the other metatype decls below.
 Q_DECLARE_METATYPE(ausstossart_et)
 Q_DECLARE_METATYPE(Segment_rt)
 typedef QPair<int, int> Coordinate;