fix: add SettingsProvider to SpeedometerViewModel and fix ProviderNotFoundException

- SpeedometerViewModel now requires both LocationRepository and SettingsProvider
- SpeedometerView uses SettingsProvider.currentTheme instead of non-existent Theme provider
- main.dart: SettingsProvider created before SpeedometerViewModel in provider hierarchy
- Restores proper DI wiring after layered architecture refactor

lib/main.dart

@@ -33,19 +33,20 @@ void main() async {
           },
         ),
         // UI layer — ViewModels subscribe to repositories
-        ChangeNotifierProvider<SpeedometerViewModel>(
-          create: (context) => SpeedometerViewModel(
-            context.read<LocationRepository>(),
-          ),
-        ),
-        ChangeNotifierProvider<OverlayViewModel>(
-          create: (_) => OverlayViewModel(),
-        ),
         ChangeNotifierProvider<SettingsProvider>(
           create: (context) => SettingsProvider(
             context.read<SharedPreferences>(),
           ),
         ),
+        ChangeNotifierProvider<SpeedometerViewModel>(
+          create: (context) => SpeedometerViewModel(
+            context.read<LocationRepository>(),
+            context.read<SettingsProvider>(),
+          ),
+        ),
+        ChangeNotifierProvider<OverlayViewModel>(
+          create: (_) => OverlayViewModel(),
+        ),
       ],
       child: const SpeedoApp(),
     ),

lib/ui/features/speedometer/speedometer_view.dart

@@ -5,6 +5,7 @@ import 'package:provider/provider.dart';
 import '../../../core/constants/overlay_constants.dart';
 import '../../../core/theme/color_themes.dart';
 import '../../shared/speed_display.dart';
+import '../../../providers/settings_provider.dart';
 import 'speedometer_view_model.dart';
 
 /// Thin UI view for the speedometer — renders speed and compass.
@@ -19,9 +20,8 @@ class SpeedometerView extends StatelessWidget {
       selector: (_, vm) => vm.displaySpeed,
       builder: (context, displaySpeed, _) {
         final vm = context.watch<SpeedometerViewModel>();
-        final theme = context.select<Theme, ColorTheme>(
-          (theme) => ColorThemes.themes[0],
-        );
+        final settings = context.read<SettingsProvider>();
+        final theme = settings.currentTheme;
 
         // Staleness — UI-layer concern
         final age = DateTime.now().difference(vm.displayData.timestamp);

lib/ui/features/speedometer/speedometer_view_model.dart

@@ -1,5 +1,4 @@
 import 'package:flutter/widgets.dart';
-import 'package:provider/provider.dart';
 import '../../../core/constants/speed_unit.dart';
 import '../../../data/models/location_data.dart';
 import '../../../data/repositories/location_repository.dart';
@@ -11,22 +10,16 @@ import '../../../providers/settings_provider.dart';
 /// the current display state to the view. No data-layer logic here.
 class SpeedometerViewModel extends ChangeNotifier {
   final LocationRepository _repository;
-  SettingsProvider? _settings;
+  final SettingsProvider _settings;
 
-  SpeedUnit get displayUnit => _settings?.currentUnit ?? SpeedUnit.kmh;
+  SpeedUnit get displayUnit => _settings.currentUnit;
   LocationData get displayData => _repository.currentData;
   String get displaySpeedText => _repository.currentData.displaySpeed;
   String get displayHeading => _repository.currentData.displayHeading;
   bool get isSpeedValid => _repository.currentData.isSpeedValid;
   bool get isHeadingValid => _repository.currentData.isHeadingValid;
 
-  SpeedometerViewModel(this._repository);
-
-  /// Call when the ViewModel is inserted into the provider tree so it
-  /// can listen to SettingsProvider and repository state.
-  void attach(BuildContext context) {
-    _settings = context.read<SettingsProvider>();
-  }
+  SpeedometerViewModel(this._repository, this._settings);
 
   double get displaySpeed {
     return displayUnit.convert(_repository.currentData.speed);