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/Plugins/OcSituationClient/Gui/OcTerminal/osc_demand_situation.cpp

@@ -8,7 +8,7 @@
 #include <PluginInterfaces/gui_plugin_interface.h>
 #include <LtsUtilsSettings/settings.h>
 #include <Map/map.h> 
-#include <QTreeView>
+#include <QtWidgets/QTreeView>
 
 namespace OcSituationClient
 {

qt6-after/qt6-migrated-legatus/Lts/Plugins/OcSituationClient/Gui/OcTerminal/osc_demand_situation_filter.cpp

@@ -6,10 +6,10 @@
 #include "ui_osc_demand_situation_filter.h"
 #include <PluginInterfaces/gui_plugin_interface.h>
 #include <LtsUtilsSettings/settings.h>
-#include <QVBoxLayout>
-#include <QLayout>
-#include <QCheckBox>
-#include <QLabel>
+#include <QtWidgets/QVBoxLayout>
+#include <QtWidgets/QLayout>
+#include <QtWidgets/QCheckBox>
+#include <QtWidgets/QLabel>
 
 namespace OcSituationClient
 {

qt6-after/qt6-migrated-legatus/Lts/Plugins/OcSituationClient/Gui/OcTerminal/osc_demand_situation_filter.h

@@ -15,7 +15,7 @@
 #include <ParticipantManagement/ppm.hpp>
 #include <set>
 
-#include <QWidget>
+#include <QtWidgets/QWidget>
 
 namespace Ui {
 class DemandSituationFilter;

qt6-after/qt6-migrated-legatus/Lts/Plugins/OcSituationClient/Gui/OcTerminal/osc_edit_folder_content.cpp

@@ -5,8 +5,8 @@
 #include "osc_edit_folder_content.h"
 #include <utility>
 #include "ui_osc_edit_folder_content.h"
-#include <QDir>
-#include <QTableView>
+#include <QtCore/QDir>
+#include <QtWidgets/QTableView>
 #include <LtsUtilsSettings/settings.h>
 #include <LtsDataView/lts_data_view.h>
 #include <LtsSession/lts_session_data.h>

qt6-after/qt6-migrated-legatus/Lts/Plugins/OcSituationClient/Gui/OcTerminal/osc_edit_folder_content.h

@@ -9,7 +9,7 @@
 #include <LtsSession/lts_session.h>
 #include <QFileSystemModel>
 #include <nglwidgets/nglpdfwidget.h>
-#include <QSortFilterProxyModel>
+#include <QtCore/QSortFilterProxyModel>
 #include <LtsUtils/LtsUtilsGui/LtsUtilsGuiDds/request_helper.h>
 
 #include <Plugins/OcBaseDownload/obd_data_plugin_interface.h>

qt6-after/qt6-migrated-legatus/Lts/Plugins/OcSituationClient/Gui/OcTerminal/osc_terminal_gui_plugin.cpp

@@ -16,11 +16,11 @@
 #include <ParticipantManagement/ppm_data_plugin_interface.h>
 #include <ParticipantManagement/ppm_gui_combobox_plugin_interface.h>
 #include <Map/map.h> 
-#include <QTimer>
+#include <QtCore/QTimer>
 #include <LtsWidgets/lts_base_layout_widget.h>
-#include <QPainter>
-#include <QImage>
-#include <QRect>
+#include <QtGui/QPainter>
+#include <QtGui/QImage>
+#include <QtCore/QRect>
 #include <QRadialGradient>
 
 namespace OcSituationClient