Qt6 Migration: Merge latest Qt5 devel content and apply migration fixes

- Merged 292 changed files from dlbo snapshot
- Fixed IDL enum collisions (PortType, PdmEventType)
- Fixed Grantlee template for C++11 scoped enums
- Fixed CMake VERSION_GREATER syntax
- Added missing directories (THP, LtsRestClient, etc.)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Lts/Common/LtsRestClient/lts_rest_client.h

@@ -0,0 +1,51 @@
+/**
+ * Lightweight REST Client Framework
+ * $Id$
+ * $HeadURL$
+ * $Author$
+ * Created by Hannes Fritsche, ESZS, 2026-08-21
+ */
+
+// Short documentation on how to use it can be found at https://confluence-classified.rh-int.de/spaces/LEG/pages/207915647/HOWTO+LtsRestClient
+
+#pragma once
+
+#include <QJsonDocument>
+#include <QObject>
+#include <QString>
+#include <functional>
+#include <LtsRestClient/ltsrestclient_export.h>
+
+class QNetworkAccessManager;
+
+namespace LtsCommon
+{
+
+class LTSRESTCLIENT_EXPORT LtsRestClient : public QObject
+{
+  Q_OBJECT
+
+  public:
+  explicit LtsRestClient(const QString &baseUrl, QObject *parent = nullptr);
+
+  // type aliases
+  using PingSuccessCallback = std::function<void(int statusCode)>;
+  using SuccessCallback = std::function<void(const QJsonDocument &)>;
+  using ErrorCallback = std::function<void(const QString &)>;
+
+  // HTTP Header Ping to m_baseUrl to check server availability
+  void ping(PingSuccessCallback onSuccess, ErrorCallback onError = nullptr, int timeoutMs = 3000);
+
+  // HTTP Methods
+  void get(const QString &endpoint, SuccessCallback onSuccess, ErrorCallback onError = nullptr);
+  void post(const QString &endpoint, const QJsonDocument &json, SuccessCallback onSuccess, ErrorCallback onError = nullptr);
+  void put(const QString &endpoint, const QJsonDocument &json, SuccessCallback onSuccess, ErrorCallback onError = nullptr);
+  void del(const QString &endpoint, SuccessCallback onSuccess, ErrorCallback onError = nullptr);
+
+  private:
+  void sendRequest(const QString &method, const QString &endpoint, const QByteArray &data, SuccessCallback onSuccess, ErrorCallback onError);
+
+  QString m_baseUrl;
+  QNetworkAccessManager *m_manager;
+}; // class RestClient
+} // namespace LtsCommon