Merge feature/lts-viewer-validation-testing-phase into feature/qt6-migration-basis-modules-merge

Resolves 1 conflict (new_docker_build.sh, union of viewer-only + codification options); folds in fixes for pre-existing defects surfaced by the validation runs (KDReports-qt6 wiring, LtsSession RTI linking, LtsFileDialog/WLS/BSM Qt6/RTI API migration, GROUP4 target list, new --cmake_build_flags option); validated with BUILD_RTI=ON BUILD_GRANTLEE=ON in 3 Docker runs (run 3: build green, 6 base-state first-run CTest failures documented).

qt6-after/qt6-migrated-legatus/Lts/Viewer/LtsFileDialog/test.cpp

@@ -9,6 +9,7 @@
 
 #include "lts_file_dialog.h"
 #include <QtWidgets/QApplication>
+#include <QTimer>
 #include <NGLLogger/NGLLoggerBootstrap.h>
 #include <DDS/DDSConnector/dds_connector.h>
 
@@ -61,6 +62,9 @@ int main(int argc, char **argv)
 
   view->show();
 
+  // Auto-exit for CI/headless testing
+  QTimer::singleShot(1000, &app, &QApplication::quit);
+
   int ret = app.exec();
 
   view->deleteLater();