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(),
     ),