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/Services/AudioVideoManagement/ava_session.h

@@ -0,0 +1,94 @@
+/**
+  * @RDE_HEADER@
+  * AvaCommSession
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Christian Fröbel, SLSE, 2017-07-17
+  */
+
+#pragma once
+
+#include "avm_export.h"
+#include "ava_types.h"
+#include "logger.h"
+#include <QObject>
+#include <QString>
+#include <QTimer>
+
+
+namespace AudioVideoManagement
+{
+
+class AvaControl;
+
+/**
+ * The session is responsible for
+ * - observing the connection to AVS
+ * - regularly issuing a KeepAlive
+ * - setting the context and user profile after a successful connect.
+ *
+ * In the application there are several clients communicating with the AVS
+ * via a single AvaControl-instance.
+ * When the connection breaks down for some reason it will be re-established.
+ * After that there must be one single instance which is responsible
+ * to again set the context and user profile for the session.
+ * The other clients may continue to communicate with the AVS only after
+ * context and profile have been set.
+ *
+ * @author Christian Fröbel
+ */
+class AVM_COMMON_EXPORT AvaSession : public QObject
+{
+  Q_OBJECT
+
+public:
+  AvaSession(AvaControl *ctrl, int exerciseId, const QString &operator_, const QString &langCode, AvaAudioPrio, QChar timezone, AvaGuiStyle, bool keepAliveEnabled);
+
+  /**
+   * Access to underlying AvaControl instance.
+   * @return never nullptr
+   */
+  AvaControl *control() { return m_ctrl; }
+
+  bool isEstablished() const { return m_established; }
+
+public slots:
+  /**
+   * Connected by AvsSessionConext to AudioPrioObserver::audioPrioChanged().
+   */
+  void onAudioPrioChanged(AvaAudioPrio newPrio);
+
+  /**
+   * Connected by AvsSessionConext to AudioPrioObserver::timezoneChanged().
+   */
+  void onTimezoneChanged(QChar newTimezone);
+  
+signals:
+  /**
+   * Will be emitted after the connection to AVS has successfully been established
+   * and context and user profile have been set.
+   */
+  void sessionEstablished();
+  void disconnected();
+
+private slots:
+  void onConnected();
+  void onDisconnected();
+  void onKeepAliveTimerElapsed();
+
+private:
+  AvaControl   *m_ctrl;
+  bool          m_established{false};
+  int           m_exerciseId;
+  QString       m_operator;
+  QString       m_langCode;
+  AvaAudioPrio  m_audioPrio;
+  QChar         m_timezone;
+  AvaGuiStyle   m_guiStyle;
+  const bool    m_keepAliveEnabled;
+  QTimer        m_keepAliveTimer;
+  LOGGER_T      m_logger;
+};
+
+} // namespace AudioVideoManagement