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/Z/src/QtSingleApplication/qtlocalpeer.cpp

@@ -3,13 +3,13 @@
 
 
 #include "qtlocalpeer.h"
-#include <QCoreApplication>
-#include <QDataStream>
-#include <QTime>
-#include <QRegularExpression>
+#include <QtCore/QCoreApplication>
+#include <QtCore/QDataStream>
+#include <QtCore/QTime>
+#include <QtCore/QRegularExpression>
 
 #if defined(Q_OS_WIN)
-#include <QLibrary>
+#include <QtCore/QLibrary>
 #include <qt_windows.h>
 typedef BOOL(WINAPI*PProcessIdToSessionId)(DWORD,DWORD*);
 static PProcessIdToSessionId pProcessIdToSessionId = 0;

qt6-after/qt6-migrated-legatus/Z/src/QtSingleApplication/qtlocalpeer.h

@@ -4,9 +4,9 @@
 #ifndef QTLOCALPEER_H
 #define QTLOCALPEER_H
 
-#include <QLocalServer>
-#include <QLocalSocket>
-#include <QDir>
+#include <QtNetwork/QLocalServer>
+#include <QtNetwork/QLocalSocket>
+#include <QtCore/QDir>
 
 #include "qtlockedfile.h"
 

qt6-after/qt6-migrated-legatus/Z/src/QtSingleApplication/qtlockedfile.h

@@ -4,9 +4,9 @@
 #ifndef QTLOCKEDFILE_H
 #define QTLOCKEDFILE_H
 
-#include <QFile>
+#include <QtCore/QFile>
 #ifdef Q_OS_WIN
-#include <QVector>
+#include <QtCore/QVector>
 #endif
 
 #if defined(Q_OS_WIN)

qt6-after/qt6-migrated-legatus/Z/src/QtSingleApplication/qtlockedfile_win.cpp

@@ -4,7 +4,7 @@
 #include "qtlockedfile.h"
 #include <utility>
 #include <qt_windows.h>
-#include <QFileInfo>
+#include <QtCore/QFileInfo>
 
 #define MUTEX_PREFIX "QtLockedFile mutex "
 

qt6-after/qt6-migrated-legatus/Z/src/QtSingleApplication/qtsingleapplication.cpp

@@ -4,7 +4,7 @@
 
 #include "qtsingleapplication.h"
 #include "qtlocalpeer.h"
-#include <QWidget>
+#include <QtWidgets/QWidget>
 
 
 

qt6-after/qt6-migrated-legatus/Z/src/QtSingleApplication/qtsingleapplication.h

@@ -4,7 +4,7 @@
 #ifndef QTSINGLEAPPLICATION_H
 #define QTSINGLEAPPLICATION_H
 
-#include <QApplication>
+#include <QtWidgets/QApplication>
 
 class QtLocalPeer;
 

qt6-after/qt6-migrated-legatus/Z/src/QtSingleApplication/qtsinglecoreapplication.h

@@ -4,7 +4,7 @@
 #ifndef QTSINGLECOREAPPLICATION_H
 #define QTSINGLECOREAPPLICATION_H
 
-#include <QCoreApplication>
+#include <QtCore/QCoreApplication>
 
 class QtLocalPeer;