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/Common/LtsWidgets/lts_elided_label.cpp

@@ -0,0 +1,66 @@
+/**
+  * @RDE_HEADER@
+  * LtsWidget - a QLabel which elides the text if necessary
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Christian Ehrlicher, NLE, 2018-12-17
+  */
+
+#include "lts_elided_label.h"
+
+#include <QPaintEvent>
+#include <QResizeEvent>
+
+
+namespace LtsWidgets
+{
+void LtsElidedLabel::setElideMode(Qt::TextElideMode elideMode)
+{
+  m_elideMode = elideMode;
+  m_cachedText.clear();
+  update();
+}
+
+void LtsElidedLabel::resizeEvent(QResizeEvent *e)
+{
+  QLabel::resizeEvent(e);
+  m_cachedText.clear();
+}
+
+void LtsElidedLabel::paintEvent(QPaintEvent *e)
+{
+  if (m_elideMode == Qt::ElideNone)
+    return QLabel::paintEvent(e);
+
+  updateCachedTexts();
+  QLabel::setText(m_cachedElidedText);
+  QLabel::paintEvent(e);
+  QLabel::setText(m_cachedText);
+}
+
+void LtsElidedLabel::updateCachedTexts()
+{
+  // setText() is not virtual ... :/
+  const auto txt = text();
+  if (m_cachedText == txt)
+    return;
+  m_cachedText = txt;
+  const QFontMetrics fm(fontMetrics());
+  m_cachedElidedText = fm.elidedText(text(),
+                                     m_elideMode,
+                                     width(),
+                                     Qt::TextShowMnemonic);
+  if (!m_cachedText.isEmpty())
+  {
+    const QString showFirstCharacter = m_cachedText.at(0) + QStringLiteral("...");
+#if QT_VERSION < QT_VERSION_CHECK(5, 11, 0)
+    const int width = fm.width(showFirstCharacter);
+#else
+    const int width = fm.horizontalAdvance(showFirstCharacter);
+#endif
+    setMinimumWidth(width + 1);
+  }
+}
+
+} // namespace LtsWidgets