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/CentralEffectSimulation/main_handler.h

@@ -0,0 +1,79 @@
+/**
+  * MainHandler for Messaging
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by hjl, SLSE, 2016-09-21
+  */
+
+#pragma once
+
+#include "ces_plugin_interface.h"
+#include "handler_participant.h"
+#include "handler_building_data.h"
+#include "proxy_building.h"
+#include "dds_handler.h"
+
+#include <CentralEffectSimulation/logger.h>
+#include <CentralEffectSimulation/svccesddscommon_export.h>
+
+namespace NGLDB
+{
+template <typename DB> class DbServiceHandler;
+}
+
+namespace LtsPluginManager
+{
+struct PluginInstance;
+}
+
+
+namespace LtsPluginManager
+{
+struct PluginInstance;
+}
+
+
+namespace CentralEffectSimulation
+{
+
+class SVCCESDDSCOMMON_EXPORT MainHandler : public QObject, public Plugin::DataProvider
+{
+  Q_OBJECT
+public:
+  explicit MainHandler(QObject *parent = nullptr);
+  ~MainHandler();
+
+  bool init(int domainId, int exerciseId);
+
+  std::shared_ptr<DdsHandler>        dds() const                    { return m_ddsHandler;      }
+  std::shared_ptr<DatabaseInterface> db() const                     { return m_dbHandler->db(); }
+
+  std::shared_ptr<HandlerBuildingData> handlerBuildingData() const  { return m_handlerBuildingData; }
+  std::shared_ptr<HandlerParticipant>  handlerParticipant() const   { return m_handlerParticipant;  }
+
+  std::shared_ptr<ProxyBuilding>        proxyBuilding() const       { return m_proxyBuilding;  }
+
+  const std::vector<std::shared_ptr<Plugin::Interface>> &getPluginList() const { return m_interfaces; }
+
+
+private:
+  bool loadPlugin(const LtsPluginManager::PluginInstance &pi);
+
+private: // attributes
+  std::shared_ptr<DdsHandler>                        m_ddsHandler;
+  std::shared_ptr<DbHandler>                         m_dbHandler;
+  std::shared_ptr<DatabaseInterface>                 m_db;
+  std::shared_ptr<HandlerBuildingData>               m_handlerBuildingData;
+  std::shared_ptr<HandlerParticipant>                m_handlerParticipant;
+  std::vector<std::shared_ptr<Plugin::Interface>>    m_interfaces;
+
+  std::shared_ptr<ProxyBuilding>                     m_proxyBuilding;
+
+
+  int                                                m_domainId = 0;
+  int                                                m_exerciseId = 0;
+  CentralEffectSimulation::LOGGER_T                 &m_logger;           ///< Interface to the Logging-Facility
+
+};
+} // namespace CentralEffectSimulation