Add ability to select distance unit

lib/components/pages/stats.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
 import 'package:mileograph_flutter/objects/objects.dart';
 import 'package:mileograph_flutter/services/data_service.dart';
+import 'package:mileograph_flutter/services/distance_unit_service.dart';
 import 'package:provider/provider.dart';
 
 class StatsPage extends StatefulWidget {
@@ -12,7 +13,6 @@ class StatsPage extends StatefulWidget {
 }
 
 class _StatsPageState extends State<StatsPage> {
-  final NumberFormat _mileageFormat = NumberFormat('#,##0.##');
   final NumberFormat _countFormat = NumberFormat.decimalPattern();
 
   @override
@@ -30,16 +30,20 @@ class _StatsPageState extends State<StatsPage> {
   @override
   Widget build(BuildContext context) {
     final data = context.watch<DataService>();
+    final distanceUnits = context.watch<DistanceUnitService>();
     return Scaffold(
       appBar: AppBar(title: const Text('Stats')),
       body: RefreshIndicator(
         onRefresh: () => _loadStats(force: true),
-        child: _buildContent(data),
+        child: _buildContent(data, distanceUnits),
       ),
     );
   }
 
-  Widget _buildContent(DataService data) {
+  Widget _buildContent(
+    DataService data,
+    DistanceUnitService distanceUnits,
+  ) {
     final stats = data.aboutStats;
     final loading = data.isAboutStatsLoading;
 
@@ -79,13 +83,14 @@ class _StatsPageState extends State<StatsPage> {
       itemBuilder: (context, index) {
         return Padding(
           padding: EdgeInsets.only(bottom: index == years.length - 1 ? 0 : 12),
-          child: _buildYearCard(context, years[index]),
+          child: _buildYearCard(context, years[index], distanceUnits),
         );
       },
     );
   }
 
-  Widget _buildYearCard(BuildContext context, StatsYear year) {
+  Widget _buildYearCard(
+      BuildContext context, StatsYear year, DistanceUnitService distanceUnits) {
     final theme = Theme.of(context);
     return Card(
       child: Padding(
@@ -109,7 +114,7 @@ class _StatsPageState extends State<StatsPage> {
                     _buildInfoChip(
                       context,
                       label: 'Mileage',
-                      value: '${_mileageFormat.format(year.mileage)} mi',
+                      value: distanceUnits.format(year.mileage, decimals: 1),
                     ),
                     _buildInfoChip(
                       context,
@@ -126,25 +131,29 @@ class _StatsPageState extends State<StatsPage> {
               title: 'Top classes',
               items: year.topClasses,
               emptyLabel: 'No class data',
-              itemBuilder: (item, index) => ListTile(
-                dense: true,
-                contentPadding: const EdgeInsets.symmetric(horizontal: 8),
-                title: Text(item.locoClass),
-                trailing: Text('${_mileageFormat.format(item.mileage)} mi'),
+                itemBuilder: (item, index) => ListTile(
+                  dense: true,
+                  contentPadding: const EdgeInsets.symmetric(horizontal: 8),
+                  title: Text(item.locoClass),
+                  trailing: Text(
+                    distanceUnits.format(item.mileage, decimals: 1),
+                  ),
+                ),
               ),
-            ),
             _buildSection<StatsNetworkMileage>(
               context,
               title: 'Top networks',
               items: year.topNetworks,
               emptyLabel: 'No network data',
-              itemBuilder: (item, index) => ListTile(
-                dense: true,
-                contentPadding: const EdgeInsets.symmetric(horizontal: 8),
-                title: Text(item.network),
-                trailing: Text('${_mileageFormat.format(item.mileage)} mi'),
+                itemBuilder: (item, index) => ListTile(
+                  dense: true,
+                  contentPadding: const EdgeInsets.symmetric(horizontal: 8),
+                  title: Text(item.network),
+                  trailing: Text(
+                    distanceUnits.format(item.mileage, decimals: 1),
+                  ),
+                ),
               ),
-            ),
             _buildSection<StatsStationVisits>(
               context,
               title: 'Top stations',