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/AudioVideoManagement/active_exercises.h

@@ -0,0 +1,58 @@
+/**
+  * @RDE_HEADER@
+  * ActiveExerciseWithRadioGroup
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Christian Fröbel, NLSE, 2018-02-16
+  */
+
+#pragma once
+
+#include <QObject>
+#include <vector>
+
+
+namespace AudioVideoManagement
+{
+
+class ExercisesHandler;
+class ExerciseContext;
+
+/**
+ * The ExercisesHandler emits a signal whenever an Exercise gets activated (or deactivated).
+ * (See there for what "activated" means).
+ *
+ * @see TvcHandler
+ * @see CnrHandler
+ * @see ExercisesHandler
+ * @author Christian Fröbel
+ */
+class ActiveExercises : public QObject
+{
+  Q_OBJECT
+
+public:
+  explicit ActiveExercises(ExercisesHandler *exercisesHandler);
+  ~ActiveExercises() override;
+
+  /** Return all active Contexts. */
+  const std::vector<ExerciseContext> &allContexts() const;
+  int count() const { return m_activeExercises.size(); }
+
+  bool   isActive(const ExerciseContext &context) const;
+
+signals:
+  /** Signalled when the Exercise is active. */
+  void contextActivated(const ExerciseContext &context);
+  void contextDeactivated(const ExerciseContext &context);
+
+private slots:
+  void onContextActivated(const ExerciseContext &context);
+  void onContextDeactivated(const ExerciseContext &context);
+
+private:
+  std::vector<ExerciseContext>   m_activeExercises;
+};
+
+} // namespace AudioVideoManagement