Qt6 migration: Fix BUILD_RTI=OFF build errors in TrainingAreaBase

- training_area_telegrams.cpp: Fixed QJsonObject initializer syntax (Qt6 requires {{}} not ({}))
- training_area_telegrams.cpp: Fixed fromJson() methods to access m_* members directly
- training_area_telegrams.cpp: Fixed brace mismatches in multiple toJson() methods
- training_area_telegrams.h: Changed Header struct to public members for consistency
- tx_mixin.cpp: Fixed getEquipmentNumber() template for direct member access
- lts_coordinate.cpp: Added missing #include <iomanip>
- MIGRATION_STATUS.md: Added migration progress tracking document

C++17 constraint enforced due to RTI Connext DDS 7.7.0 incompatibility with C++20+

Build status: BUILD_RTI=OFF successful (0 errors, warnings only)

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

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/tests/lts_picture_editing.cpp

@@ -11,14 +11,14 @@
 #include "ui_lts_picture_editing.h"
 #include "lts_picture_view.h"
 
-#include <QFileDialog>
-#include <QPixmap>
-#include <QMessageBox>
-#include <QImage>
+#include <QtWidgets/QFileDialog>
+#include <QtGui/QPixmap>
+#include <QtWidgets/QMessageBox>
+#include <QtGui/QImage>
 #include <QGraphicsPixmapItem>
 
-#include <QDebug>
-#include <QTimer>
+#include <QtCore/QDebug>
+#include <QtCore/QTimer>
 
 LtsPictureEditing::LtsPictureEditing(QWidget *parent)
   : QMainWindow(parent)

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/tests/lts_picture_editing.h

@@ -9,7 +9,7 @@
 
 #pragma once
 
-#include <QMainWindow>
+#include <QtWidgets/QMainWindow>
 
 namespace Ui
 {

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/tests/lts_picture_editing_main.cpp

@@ -8,7 +8,7 @@
   */
 
 #include "lts_picture_editing.h"
-#include <QApplication>
+#include <QtWidgets/QApplication>
 #include <iostream>
 
 static void qtMsgHandler(QtMsgType type, const QMessageLogContext &, const QString &msg)

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/tests/main.cpp

@@ -1,4 +1,4 @@
-#include <QApplication>
+#include <QtWidgets/QApplication>
 
 #include "window.h"
 #include <LtsWidgets/lts_date_time_edit.h>

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/tests/window.cpp

@@ -2,8 +2,8 @@
 
 #include <LtsWidgets/lts_notification_box.h>
 
-#include <QApplication>
-#include <QHBoxLayout>
+#include <QtWidgets/QApplication>
+#include <QtWidgets/QHBoxLayout>
 
 
 namespace LtsWidgets

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/tests/window.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <QWidget>
+#include <QtWidgets/QWidget>
 
 
 namespace LtsWidgets