Refactor code structure for improved readability and maintainability

Co-authored-by: Copilot <copilot@github.com>

flutter/lib/features/meal_plan/data/meal_plan_providers.dart

@@ -11,7 +11,15 @@ final mealPlanRepositoryProvider = Provider<MealPlanRepository>((ref) {
   return MealPlanRepository(ref.watch(apiClientProvider));
 });
 
-final mealPlanWeekOffsetProvider = StateProvider<int>((ref) => 0);
+class _IntNotifier extends Notifier<int> {
+  _IntNotifier(this._initial);
+  final int _initial;
+  @override
+  int build() => _initial;
+}
+
+final mealPlanWeekOffsetProvider =
+    NotifierProvider<_IntNotifier, int>(() => _IntNotifier(0));
 
 final mealPlanWeekProvider = Provider<MealPlanWeek>((ref) {
   final offset = ref.watch(mealPlanWeekOffsetProvider);

flutter/lib/features/meal_plan/data/meal_plan_repository.dart

@@ -12,14 +12,14 @@ class MealPlanRepository {
 
   Future<List<MealPlanEntry>> fetchEntries(String from, String to, {String? token}) async {
     try {
-      final data = await _api.getJson(MealPlanApiPaths.listByRange(from, to), token: token);
+      final dynamic data = await _api.getJson(MealPlanApiPaths.listByRange(from, to), token: token);
       if (data is! List) {
         throw const ApiException(
           type: ApiErrorType.unknown,
           message: 'Ogiltigt svar från servern.',
         );
       }
-      return data
+      return (data as List)
           .map((item) => MealPlanEntry.fromJson(item as Map<String, dynamic>))
           .toList();
     } on ApiException {
@@ -34,14 +34,14 @@ class MealPlanRepository {
 
   Future<List<ShoppingItem>> fetchShoppingList(String from, String to, {String? token}) async {
     try {
-      final data = await _api.getJson(MealPlanApiPaths.shoppingList(from, to), token: token);
+      final dynamic data = await _api.getJson(MealPlanApiPaths.shoppingList(from, to), token: token);
       if (data is! List) {
         throw const ApiException(
           type: ApiErrorType.unknown,
           message: 'Ogiltigt svar från servern.',
         );
       }
-      return data
+      return (data as List)
           .map((item) => ShoppingItem.fromJson(item as Map<String, dynamic>))
           .toList();
     } on ApiException {
@@ -56,14 +56,14 @@ class MealPlanRepository {
 
   Future<List<InventoryCompareItem>> fetchInventoryCompare(String from, String to, {String? token}) async {
     try {
-      final data = await _api.getJson(MealPlanApiPaths.inventoryCompare(from, to), token: token);
+      final dynamic data = await _api.getJson(MealPlanApiPaths.inventoryCompare(from, to), token: token);
       if (data is! List) {
         throw const ApiException(
           type: ApiErrorType.unknown,
           message: 'Ogiltigt svar från servern.',
         );
       }
-      return data
+      return (data as List)
           .map((item) => InventoryCompareItem.fromJson(item as Map<String, dynamic>))
           .toList();
     } on ApiException {

flutter/lib/features/meal_plan/presentation/meal_plan_screen.dart

@@ -87,8 +87,8 @@ class _MealPlanScreenState extends ConsumerState<MealPlanScreen> {
       );
     }
 
-    final recipes = recipesAsync.valueOrNull ?? const <Recipe>[];
-    final dashboard = dashboardAsync.valueOrNull ??
+    final recipes = recipesAsync.maybeWhen(data: (d) => d, orElse: () => null) ?? const <Recipe>[];
+    final dashboard = dashboardAsync.maybeWhen(data: (d) => d, orElse: () => null) ??
         const MealPlanDashboard(
           entries: [],
           shoppingItems: [],