feat: add Flutter web frontend with authentication and recipe management features

flutter/lib/features/recipes/data/recipe_providers.dart

@@ -0,0 +1,14 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import '../../../core/api/api_providers.dart';
+import '../../../features/auth/data/auth_providers.dart';
+import 'recipe_repository.dart';
+import '../domain/recipe.dart';
+
+final recipeRepositoryProvider = Provider<RecipeRepository>((ref) {
+  return RecipeRepository(ref.watch(apiClientProvider));
+});
+
+final recipesProvider = FutureProvider<List<Recipe>>((ref) async {
+  final token = await ref.watch(authStateProvider.future);
+  return ref.watch(recipeRepositoryProvider).fetchRecipes(token: token);
+});

flutter/lib/features/recipes/data/recipe_repository.dart

@@ -0,0 +1,20 @@
+import 'dart:convert';
+import '../../../core/api/api_client.dart';
+import '../domain/recipe.dart';
+
+class RecipeRepository {
+  final ApiClient _api;
+
+  RecipeRepository(this._api);
+
+  Future<List<Recipe>> fetchRecipes({String? token}) async {
+    final response = await _api.get('/api/recipes', token: token);
+    if (response.statusCode != 200) {
+      throw Exception('Failed to load recipes: ${response.statusCode}');
+    }
+    final List<dynamic> data = jsonDecode(response.body) as List<dynamic>;
+    return data
+        .map((e) => Recipe.fromJson(e as Map<String, dynamic>))
+        .toList();
+  }
+}