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/vd_session.cpp

@@ -0,0 +1,58 @@
+/**
+  * @RDE_HEADER@
+  * VdSession
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Astrid Müller, SGAS, 2018-02-26
+  */
+
+#include "vd_session.h"
+#include "vd_control.h"
+#include "ivd_comm.h"
+
+namespace AudioVideoManagement
+{
+
+VdSession::VdSession(VdControl *ctrl, int exerciseId, bool keepAliveEnabled)
+  : m_ctrl(ctrl)
+  , m_exerciseId(exerciseId)
+  , m_keepAliveEnabled(keepAliveEnabled)
+  , m_logger(getLogger("AvaSession"))
+{
+  Q_ASSERT(ctrl);
+
+  m_keepAliveTimer.setInterval(std::chrono::milliseconds(5000).count());
+  m_keepAliveTimer.setSingleShot(true);
+
+  connect(m_ctrl->comm(), &IVdComm::connected, this, &VdSession::onConnected);
+  connect(m_ctrl->comm(), &IVdComm::disconnected, this, &VdSession::onDisconnected);
+  connect(&m_keepAliveTimer, &QTimer::timeout, this, &VdSession::onKeepAliveTimerElapsed);
+}
+
+void VdSession::onConnected()
+{
+  m_ctrl->switchContext(m_exerciseId);
+
+  m_established = true;
+  if (m_keepAliveEnabled)
+    m_keepAliveTimer.start();
+  DEBUG_LOG(m_logger) << "session established";
+  emit sessionEstablished();
+}
+
+void VdSession::onDisconnected()
+{
+  m_keepAliveTimer.stop();
+  m_established = false;
+  DEBUG_LOG(m_logger) << "disconnected";
+  emit disconnected();
+}
+
+void VdSession::onKeepAliveTimerElapsed()
+{
+  m_ctrl->keepAlive();
+  m_keepAliveTimer.start();
+}
+
+} // namespace AudioVideoManagement