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/Viewer/SituationMap/Map/viewshed.h

@@ -0,0 +1,110 @@
+/**
+  * @RDE_HEADER@
+  * Interface of Viewshed
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  */
+
+#pragma once
+
+// Own
+#include "situation_map_types.h"
+#include "viewshed_parameter.h"
+#include <situation_map_export.h>
+
+
+// Qt
+#include <QObject>
+#include <QString>
+#include <QPointF>
+
+
+//----------------------------------------------------------------------------
+namespace SituationMap
+{
+
+/**
+ * @brief The Viewshed class creating a viewshed.
+ */
+class SITUATIONMAP_EXPORT Viewshed : public QObject
+{
+  using BaseClass = QObject;
+
+  Q_OBJECT
+
+public:
+  Viewshed()          = default;  ///< Contructor
+  virtual ~Viewshed() = default;  ///< Destructor
+
+  Viewshed(const Viewshed &other)     = delete;
+  Viewshed &operator=(Viewshed &other) = delete;
+
+  /**
+   * Defines URL to elevation data service or file with elevation data 
+   *
+   */
+  virtual void setViewshedUrl(const QString &viewshedServiceUrl) = 0;
+
+  /**
+    * Creates ESRI based viewshed and starts a rubberband to define the area to analyse. On success the return value is true. 
+    */
+  virtual bool create() = 0;
+
+  /**
+   * Creates a GeISiR fan of sight and starts a rubberband to define the area (center point and radius) to analyse.
+   *
+   * @param alpha          Alpha value to apply to predefined colors SightFan.
+   * @param innerRadius    Distance from center point to start the analyse.
+   * @param observerHeight Height of center point above terrain.
+   * @param targetHeight   Height of visible objects or targets.
+   * @param beamAngle      Beam width in degree of a single scan line.
+   *
+   * @return true on success
+   */
+  virtual bool create(double alpha, double innerRadius, double observerHeight, double targetHeight, double beamAngle) = 0; // will start a rubberband to create a fan of sight
+  
+  /** 
+   * Create a viewshed from existing parameter settings.
+   * 
+   * @return true on success
+   */
+  virtual long create(const ViewshedParameter &viewshedParameter) = 0;
+
+  /**
+   * In case of using GeSiR fan of sight for analysing modify the parameter settings.
+   *
+   * @param viewshedId     Id of viewshed. In case of viewshedId is "-1" the current viwshed (last created) will be modified
+   * @param alpha          Alpha value to apply to predefined colors SightFan.
+   * @param innerRadius    Distance from center point to start the analyse.
+   * @param observerHeight Height of center point above terrain.
+   * @param targetHeight   Height of visible objects or targets.
+   * @param beamAngle      Beam width in degree of a single scan line.
+   *
+   * @return true on success 
+   */
+  virtual bool modify(long viewshedId, double alpha, double innerRadius, double observerHeight, double targetHeight, double beamAngle) = 0;
+
+  /**
+   * Remove a viewshed. In case of viewshedId is "-1" all viewsheds will be removed.
+   * @param vieweshedId Id of viewshed or "-1"
+   */
+  virtual void remove(long viewshedId = -1) = 0;
+
+  /**
+   * Get parameter of a viewshed. In case of viewshedId is "-1" the current viwshed (last created) will be used 
+   * @param vieweshedId Id of viewshed or "-1"
+   * @param ok          Pointer bool variable set to true on success.
+   *
+   * @return Struct with viewshed parameters.
+   */
+  virtual ViewshedParameter getViewshedParameter(long viewshedId = -1, bool *ok = nullptr) const = 0;
+
+Q_SIGNALS:
+  void viewshedFinished(long viewshedId);
+};
+
+
+
+} // namespace SituationMap
+