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/Plugins/AudioVideoManagement/Shared/avs_app.h

@@ -0,0 +1,87 @@
+/**
+  * @RDE_HEADER@
+  * AvsApp
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Christian Fröbel, NLSE, 2018-04-16
+  */
+
+#pragma once
+
+#include <Plugins/AudioVideoManagement/Shared/avmshared_export.h>
+#include <QObject>
+#include <QRect>
+#include <boost/optional.hpp>
+
+namespace LtsMultiMonitor
+{
+class FullscreenVideoDummyWidget;
+}
+
+namespace AudioVideoManagement
+{
+
+class AvaControl;
+
+/**
+ * Manages an AVS-dialog in a way that it will behave like an Excon-App.
+ * When show() is called and the dialog is not visible yet, the Operator
+ * needs to choose on which screen the App shall be placed.
+ * The AVS-dialog will open in full-screen on the selected screen then.
+ * You can call hide() explicitly in order to hide the App. But usually
+ * this is done implicitly when a new App is placed ontop of this AvsApp.
+ *
+ * You can also call show(const QRect &geometry) in case you already know
+ * where the app is to be placed and thus avoid the screen selection.
+ *
+ * @author Christian Fröbel
+ */
+class AVMSHARED_EXPORT AvsApp : public QObject
+{
+  Q_OBJECT
+
+public:
+  AvsApp(const QString &dialogId, AvaControl *avaControl);
+  ~AvsApp() override;
+
+  void show(const QVector<QWidget *> irreplacableWidgets = {});
+  void show(const QRect &geometry);
+  void hide(bool andClose = false);
+  bool isVisible() const;
+  bool isActive() const; // may be visible or hidden, but a ScreenPlaycementHelper is still there, so it might be hidden by the switcher
+
+  /**
+   * Release alls streams that might still be active in this app.
+   * Will be called implicitly when the dialog is hidden.
+   * But it can be called explicitly, e.g. when a PlaybackApp of Type Normal is released
+   * in which case the App remaines visible (hide() is not called then).
+   */
+  void releaseStreams();
+
+signals:
+  void signalVisible();
+  void signalPause();
+  void signalResume();
+
+private slots:
+  void onWidgetPlaced(const QRect &geometry);
+  void onPlacementHelperDestroyed();
+  void onHideVideo();
+  void onShowVideo();
+
+private:
+  void showAvsDialog(const QRect &geometry);
+  void hideAvsDialog();
+  void hideAndPauseAvsDialog();
+  void showAndResumeAvsDialog();
+
+  static const QString               ALL_STREAMS;
+  const QString                      m_dialogId;
+  AvaControl                        *m_avaControl;
+  LtsMultiMonitor::FullscreenVideoDummyWidget   *m_screenPlacementHelper{nullptr};
+  boost::optional<QRect>             m_presetGeometry;
+  bool                               m_visible;
+};
+
+} // namespace AudioVideoManagement