Fix Qt6 deprecated API in LtsWidgets

- Replace invalidateFilter() with beginFilterChange()/endFilterChange() in lts_column_filter_proxy_model.cpp (3 calls)
- Replace QCheckBox::stateChanged with checkStateChanged in lts_dialog.cpp

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

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/lts_column_filter_proxy_model.cpp

@@ -63,7 +63,8 @@ void LtsColumnFilterProxyModel::setColumnStringFilter(const QString &newFilterSt
       it.value() = rx;
     }
   }
-  invalidateFilter();
+  beginFilterChange();
+  endFilterChange();
 }
 
 void LtsColumnFilterProxyModel::setColumnDataFilter(const QVariant &newFilterData, int column)
@@ -90,7 +91,8 @@ void LtsColumnFilterProxyModel::setColumnDataFilter(const QVariant &newFilterDat
       it.value() = newFilterData;
     }
   }
-  invalidateFilter();
+  beginFilterChange();
+  endFilterChange();
 }
 
 
@@ -138,7 +140,8 @@ void LtsColumnFilterProxyModel::setRecursiveFilteringEnabled(bool recursive)
   if (m_bRecursiveFiltering == recursive)
     return;
   m_bRecursiveFiltering = recursive;
-  invalidateFilter();
+  beginFilterChange();
+  endFilterChange();
 }
 
 bool LtsColumnFilterProxyModel::recursiveFilteringEnabled() const

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/lts_dialog.cpp

@@ -389,7 +389,7 @@ void LtsDialog::addConnections(QWidget *widget)
   if (addChangesMadeSignal<QLineEdit>(widget, &QLineEdit::textChanged)) return;
   if (addChangesMadeSignal<QDateTimeEdit>(widget, &QDateTimeEdit::dateTimeChanged)) return;
   if (addChangesMadeSignal<QComboBox>(widget, &QComboBox::currentTextChanged)) return;
-  if (addChangesMadeSignal<QCheckBox>(widget, &QCheckBox::stateChanged)) return;
+  if (addChangesMadeSignal<QCheckBox>(widget, &QCheckBox::checkStateChanged)) return;
   if (addChangesMadeSignal<QSpinBox>(widget, static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged))) return;
   if (addChangesMadeSignal<QDoubleSpinBox>(widget, static_cast<void (QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged))) return;
   if (addChangesMadeSignal<QSlider>(widget, &QSlider::valueChanged)) return;