Merge feature/qt6-migration-basis-modules-services into feature/qt6-migration-basis-modules

Resolves 17 conflicts against legacy Qt5 semantics; validates with BUILD_RTI=ON BUILD_GRANTLEE=ON.

qt6-after/qt6-migrated-legatus/.forward-declarations/include/MarkerManagement/mrk_dtc.h

@@ -0,0 +1,58 @@
+#pragma once
+
+// STUB-HEADER: Diese Datei wird normalerweise von ddsdtc generiert
+// Für die Migration erstellen wir minimale Forward-Declarations
+
+#include <cstdint>
+#include <functional>
+#include <optional>
+#include <string>
+#include <vector>
+
+#include <QtCore/QObject>
+
+#include "LtsUtils/LtsUtilsCore/data_modification_enum.h"
+#include "mrk_marker.h"
+
+namespace MarkerManagement
+{
+
+namespace Interface
+{
+
+// Dtc interface class with signals for Qt6 migration STUB
+class Dtc : public QObject
+{
+    Q_OBJECT
+public:
+    explicit Dtc(QObject* parent = nullptr) : QObject(parent) {}
+    ~Dtc() override = default;
+
+    // Callback registration instead of enableNotification()
+    void markers(std::function<void(const Marker&)> callback)
+    {
+        m_markerCallback = callback;
+    }
+
+    // Trigger marker changed (for STUB testing)
+    void triggerMarkerChanged(const Marker& marker, DataModification modType)
+    {
+        emit markerChanged(marker, modType);
+        if (m_markerCallback)
+        {
+            m_markerCallback(marker);
+        }
+    }
+
+signals:
+    void markerChanged(const Marker& marker, DataModification modType);
+
+private:
+    std::function<void(const Marker&)> m_markerCallback;
+};
+
+class Ftc;
+
+} // namespace Interface
+
+} // namespace MarkerManagement