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/Common/LtsProjectionWorkstation/WebSocket/messages.cpp

@@ -175,7 +175,13 @@ bool CTS::DisconnectRequest::hasValidData() const
     return true;
 }
 
-LtsProjectionWorkstation::ErrorMessage::ErrorMessage(const QString& uuid, const QString& reason)
+// Unqualified: we are already inside namespace LtsProjectionWorkstation, and the unity
+// build concatenates lts_projection_workstation.cpp (which declares
+// class LtsProjectionWorkstation in this same namespace) into this TU, so
+// "LtsProjectionWorkstation::ErrorMessage" would resolve to the class (which has no
+// such member) instead of the namespace. In a separate TU (legacy structure) the
+// class is not visible here and the qualified name resolved to the namespace.
+ErrorMessage::ErrorMessage(const QString& uuid, const QString& reason)
     : Message(nullptr, nullptr, JsonKeys::ERROR_MESSAGE(), uuid, QJsonValue()), m_reason(reason)
 {
     QJsonObject result;
@@ -183,7 +189,7 @@ LtsProjectionWorkstation::ErrorMessage::ErrorMessage(const QString& uuid, const
     m_replyData = result;
 }
 
-void LtsProjectionWorkstation::ErrorMessage::process()
+void ErrorMessage::process()
 {
     if (!m_handler || !m_client)
         return;
@@ -192,7 +198,7 @@ void LtsProjectionWorkstation::ErrorMessage::process()
     m_handler->handleMessage(this);
 }
 
-bool LtsProjectionWorkstation::ErrorMessage::hasValidData() const
+bool ErrorMessage::hasValidData() const
 {
     if (!m_handler || !m_client)
         return false;