Qt6 Migration: Complete migration with DDS/RTI support and build validation

Major Changes:
- Merged latest Qt5 devel content from dlbo (292 files changed, 7 new dirs)
- Consolidated forward-declarations and include folders
- Removed unneeded modules per Niklas' repo check list

Build System Fixes:
- Fixed CMake VERSION_GREATER syntax in ParticipantManagement/CMakeLists.txt
- Added VLC packages (libvlc-dev, vlc-plugin-base) to docker_build.sh
- Added PostgreSQL dev packages (libpq-dev, postgresql-server-dev-all) to Dockerfile
- Fixed locale warnings (ANSI_X3.4-1968 → C.UTF-8)
- Fixed ArcGIS SDK path warnings when BUILD_ARCGIS=OFF

Code Generation Fixes:
- Fixed IDL enum collisions (PortType→CorePortType/DdsutPortType, PdmEventType)
- Fixed Grantlee template svc_translation.cpp.grantlee:
  - Changed {{ idl_enum.name }}_def:: to {{ idl_enum.name }}::
  - Fixed .underlying() calls for C++11 scoped enums (enum class)
- Removed generated files from repo (moc_*, *_dtc.h, *_ftc.h)

Validation:
- BUILD_RTI=ON: SUCCESS
- BUILD_RTI=OFF: SUCCESS
- C++17 standard maintained for RTI 7.7 compatibility
- Ubuntu 26.04 Docker environment verified

Remaining Warnings (expected):
- BgViewer, KDChart, KDReports, Poppler-Qt6 not found (optional features)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt5-before/dlbo/Lts/Common/LtsAppDescriptor/main.cpp

@@ -0,0 +1,63 @@
+/**
+ * @RDE_HEADER@
+ * App Descriptor Editor
+ * $Id$
+ * $HeadURL$
+ * $Author$
+ *
+ * Created by Mike Wille, SLSE, 2016-10-24
+ */
+
+#include "lts_app_descriptor_editor.h"
+#include <QAction>
+#include <QApplication>
+#include <QMainWindow>
+#include <QMenuBar>
+
+int main(int argc, char *argv[])
+{
+  QApplication a(argc, argv);
+
+  QMainWindow *mainWindow = new QMainWindow();
+  QMenu *fileMenu = mainWindow->menuBar()->addMenu(QObject::tr("&File"));
+
+  QAction *openAct = new QAction(QObject::tr("&Open"), mainWindow);
+  openAct->setShortcuts(QKeySequence::Open);
+  openAct->setStatusTip(QObject::tr("Open an existing file"));
+  fileMenu->addAction(openAct);
+
+  QAction *newAct = new QAction(QObject::tr("&New"), mainWindow);
+  newAct->setShortcuts(QKeySequence::New);
+  newAct->setStatusTip(QObject::tr("Create a new App"));
+  fileMenu->addAction(newAct);
+
+  QAction *saveAct = new QAction(QObject::tr("&Save"), mainWindow);
+  saveAct->setShortcuts(QKeySequence::Save);
+  saveAct->setStatusTip(QObject::tr("Save modified file"));
+  fileMenu->addAction(saveAct);
+
+  QAction *saveAsAct = new QAction(QObject::tr("&SaveAs"), mainWindow);
+  saveAsAct->setShortcuts(QKeySequence::SaveAs);
+  saveAsAct->setStatusTip(QObject::tr("Save modified file as"));
+  fileMenu->addAction(saveAsAct);
+
+  QAction *quitAct = new QAction(QObject::tr("&Quit"), mainWindow);
+  quitAct->setShortcuts(QKeySequence::Quit);
+  quitAct->setStatusTip(QObject::tr("Quit the Application"));
+  fileMenu->addAction(quitAct);
+
+
+  LtsAppDescriptorEditor *editor = new LtsAppDescriptorEditor(mainWindow);
+  mainWindow->setCentralWidget(editor);
+  QObject::connect(openAct, &QAction::triggered, editor, &LtsAppDescriptorEditor::onOpenClicked);
+  QObject::connect(newAct, &QAction::triggered, editor, &LtsAppDescriptorEditor::onNewClicked);
+  QObject::connect(saveAct, &QAction::triggered, editor, &LtsAppDescriptorEditor::onSaveClicked);
+  QObject::connect(saveAsAct, &QAction::triggered, editor, &LtsAppDescriptorEditor::onSaveAsClicked);
+  QObject::connect(quitAct, &QAction::triggered, editor, &LtsAppDescriptorEditor::onQuitClicked);
+
+  mainWindow->show();
+
+  int ret = a.exec();
+  delete mainWindow;  // also deletes editor due to parent/child
+  return ret;
+}