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/Buildings/web_socket_handler.h

@@ -0,0 +1,54 @@
+/**
+  * Websocket interface to participant positions
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Justus Hertel, SLSE, 2017-01-11
+  */
+
+#pragma once
+
+#include <QObject>
+#include <QWebSocketServer>
+#include "building_control_handler.h"
+#include "logger.h"
+
+// Websocket Server for WebApplication
+
+namespace Buildings
+{
+
+class WebSocketHandler final: public QObject
+{
+  Q_OBJECT
+
+public:
+  explicit WebSocketHandler(const std::shared_ptr<BuildingControlHandler> &buildingControlHandler, QObject *parent = nullptr);
+  ~WebSocketHandler();
+
+  bool init(quint16 listenPort = 0);
+  bool init(const QPair<quint16, quint16> &portRange);
+  bool isConnected() const { return !m_webSockets.isEmpty(); }
+  quint16 listenPort() const { return m_webSocketServer->serverPort(); }
+  bool sendPosition();
+
+private:
+  bool sendTelegramInternal() const;
+  bool sendbuildingInfos() const;
+  QJsonObject ObjectFromString(const QString& in);
+  void triggerFlashlight(const QString &message);
+
+private Q_SLOTS:
+  void onNewMessage(const QString &message);
+  void onNewConnection();
+  void onWebSocketDisconnected();
+
+private:
+  std::shared_ptr<BuildingControlHandler>                             m_buildingControlHandler;  ///< Pointer to VOM DDS handler
+  QWebSocketServer* m_webSocketServer = nullptr;
+  QVector<QWebSocket*> m_webSockets;
+
+  LOGGER_T m_logger;
+};
+
+}