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/Proxies/TrainingAreaBaseOC/main_handler.cpp

@@ -0,0 +1,98 @@
+/**
+  * MainHandler for OC-connection to the SFM
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Philipp Dassow, NLST, 2018-01-23
+  */
+
+#include "main_handler.h"
+#include "settings.h"
+#include "logger.h"
+#include <DDS/Core/pacemaker.h>
+
+namespace TrainingAreaBaseOC
+{
+
+MainHandler::MainHandler(QObject *parent)
+  : QObject(parent)
+  , m_aesDtc(nullptr)
+  , m_aesFtc(nullptr)
+  , m_pdmDtc(nullptr)
+  , m_canagHandler(nullptr)
+  , m_connectionHandler(nullptr)
+  , m_ddsHandler(nullptr)
+  , m_rxHandler(nullptr)
+  , m_ftsHandler(nullptr)
+  , m_websocketHandler(nullptr)
+  , m_logger(getLogger("MainHandler"))
+{}
+
+MainHandler::~MainHandler()
+{
+  m_rxHandler.reset();
+  m_canagHandler.reset();
+  m_connectionHandler.reset();
+  m_ftsHandler.reset();
+  m_aesDtc.reset();
+  m_aesFtc.reset();
+  m_pdmDtc.reset();
+  m_ddsHandler.reset();
+}
+
+bool MainHandler::init(int domainId, int exerciseId)
+{
+  // initialize DDS
+  m_ddsHandler = std::make_shared<DdsHandler>(domainId, exerciseId);
+  if (!m_ddsHandler->init())
+  {
+    ERROR_LOG(m_logger) << "Could not initialise DdsHandler.";
+    return false;
+  }
+
+  // create AES Dtc
+  m_aesDtc = AreaEffectSimulation::Interface::Dtc::create(m_ddsHandler->ddsConnector());
+  DEBUG_LOG(m_logger) << "Created AES Dtc";
+
+  // create AES Ftc
+  m_aesFtc = AreaEffectSimulation::Interface::Ftc::create(m_ddsHandler->ddsConnector());
+  DEBUG_LOG(m_logger) << "Created AES Ftc";
+
+  // create PDM Dtc
+  m_pdmDtc = ProjectDataManagement::Interface::Dtc::create(m_ddsHandler->ddsConnector());
+  DEBUG_LOG(m_logger) << "Created PDM Dtc";
+
+  // ConnectionHandler
+  m_connectionHandler = std::make_shared<ConnectionHandler>();
+
+  if (!m_connectionHandler->init())
+  {
+    ERROR_LOG(m_logger) << "Could not initialise ConnectionHandler.";
+    return false;
+  }
+
+  // to DDS
+  m_rxHandler = std::make_shared<SendToDds>(this);
+
+  // CanagHandler / to TrainingArea
+  m_canagHandler = std::make_shared<CanagHandler>(this);
+
+  if (!m_canagHandler->init())
+  {
+    ERROR_LOG(m_logger) << "Could not initialise CanagHandler.";
+    return false;
+  }
+
+
+  // from DDS
+  m_ftsHandler = std::make_shared<RecvFromDdsFts>(this);
+#ifndef GUEZ_MODE
+  m_websocketHandler = std::make_shared<WebsocketHandler>(this, exerciseId, m_ddsHandler->dtsTaboc(), m_ddsHandler->dtcTaboc());
+#endif
+
+  m_ddsHandler->pacemaker()->setNewState(Core::RunningState::Running);
+
+  return true;
+}
+
+} // namespace TrainingAreaBaseOC