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/OcBaseDownload/pdf_download_socket.cpp

@@ -0,0 +1,102 @@
+/**
+  * @RDE_HEADER@
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Hannes Fritsche, NLE, 2019-04-30
+  */
+
+#include "pdf_download_socket.h"
+
+#include <nglsettings/nglsettings_connections.h>
+#include <nglsettings/nglsettings_settings.h>
+
+#include <QTimer>
+
+namespace OcBaseDownload
+{
+PdfDownloadSocket::PdfDownloadSocket(const QString &hostName, QObject *parent)
+  : QObject(parent)
+  , m_socket(new QTcpSocket(this))
+  , m_readTimeout(new QTimer(this))
+  , m_sizeToDownload(0)
+  , m_logger(getLogger("PdfDownloadSocket"))
+{
+  DEBUG_LOG(m_logger) << "PdfDownloadSocket::PdfDownloadSocket";
+  connect(m_socket, &QTcpSocket::connected, this, &PdfDownloadSocket::connected);
+  connect(m_socket, &QTcpSocket::readyRead, this, &PdfDownloadSocket::readyRead);
+  unsigned short port = NGL::Connections::port(NGL::Connections::eConnection::FLM_PDF_SERVER);
+  m_socket->connectToHost(hostName, port);
+  m_socket->waitForConnected();
+
+  DEBUG_LOG(m_logger) << "hostname " << hostName << " port " << port;
+
+  m_readTimeout->setInterval(10000);
+  m_readTimeout->setSingleShot(false);
+  connect(m_readTimeout, &QTimer::timeout, this, &PdfDownloadSocket::onReadTimeout);
+}
+
+PdfDownloadSocket::~PdfDownloadSocket()
+{
+  DEBUG_LOG(m_logger) << "~PdfDownloadSocket";
+  m_socket->close();
+}
+
+void PdfDownloadSocket::readyRead()
+{
+  DEBUG_LOG(m_logger) << "reading...";
+  m_readTimeout->stop();
+
+  m_downloadedData.append(m_socket->readAll());
+
+  DEBUG_LOG(m_logger) << m_downloadedData.size() << " of " << m_sizeToDownload << " bytes downloaded";
+
+  if (m_downloadedData.size() >= m_sizeToDownload)
+  {
+    m_sizeToDownload = 0;
+    DEBUG_LOG(m_logger) << "Download finished";
+    emit downloadFinished(m_downloadedData);
+  }
+  else
+    m_readTimeout->start();
+}
+
+void PdfDownloadSocket::connected()
+{
+  DEBUG_LOG(m_logger) << "connected...";
+}
+
+void PdfDownloadSocket::onReadTimeout()
+{
+  //check for filesize
+  m_readTimeout->stop();
+  DEBUG_LOG(m_logger) << "TimerEnd" << m_downloadedData.size() << " expected " << m_sizeToDownload;
+
+  if (m_downloadedData.size() < m_sizeToDownload)
+    WARNING_LOG(m_logger) << "not enough data: got " << m_downloadedData.size() << " expected " << m_sizeToDownload;
+
+  emit downloadFinished(m_downloadedData);
+}
+
+void PdfDownloadSocket::downloadFromHost(const int fileId, const qint64 fileSize)
+{
+  m_sizeToDownload = fileSize;
+  m_downloadedData = QByteArray();
+
+  QByteArray cmd;
+  cmd += QByteArray("PDF_DOWNLOAD ");
+  cmd += QByteArray::number(fileId);
+  cmd += "\n";
+  m_socket->readAll();
+
+  int writeHeaderSize = m_socket->write(cmd);
+  DEBUG_LOG(m_logger) << "writeHeaderSize = " << writeHeaderSize;
+  m_readTimeout->start();
+}
+
+bool PdfDownloadSocket::isConnected() const
+{
+  return m_socket->state() == QAbstractSocket::ConnectedState;
+}
+
+}