Increase default date range to 1 year; change format to dd/MM (#389)

* Show past 3 months by default in visualization tab

* Up to 1 year back in time

* Change date format to dd/MM

Author: andreped

lib/tabs/visualization_tab.dart

@@ -275,7 +275,7 @@ class VisualizationTabState extends State<VisualizationTab> {
     // Initialize the date range to the last month if not already set
     if (_selectedDateRange == null) {
       final now = DateTime.now();
-      final lastMonth = DateTime(now.year, now.month - 1, now.day);
+      final lastMonth = DateTime(now.year, now.month - 12, now.day);
       _selectedDateRange = DateTimeRange(start: lastMonth, end: now);
     }
 

lib/widgets/charts/chart_widget.dart

@@ -228,7 +228,7 @@ class ChartWidget extends StatelessWidget {
       fontSize: 14, // Increased font size
     );
     final date = DateTime.now().add(Duration(days: value.toInt()));
-    final formattedDate = DateFormat('MM/dd').format(date);
+    final formattedDate = DateFormat('dd/MM').format(date);
     return SideTitleWidget(
       axisSide: meta.axisSide,
       space: 8.0, // Increased space to move the labels downwards