feat(wip): Update entities and adopt a proper repository workflow for trip "obtention"

frontend/lib/presentation/providers/core_providers.dart

@@ -0,0 +1,49 @@
+import 'package:anyway/core/dio_client.dart';
+import 'package:anyway/data/repositories/local_onboarding_repository.dart';
+import 'package:anyway/domain/repositories/onboarding_repository.dart';
+import 'package:anyway/domain/repositories/trip_repository.dart';
+import 'package:anyway/data/repositories/backend_trip_repository.dart';
+import 'package:anyway/data/datasources/trip_remote_datasource.dart';
+import 'package:anyway/data/repositories/preferences_repository_impl.dart';
+import 'package:anyway/domain/repositories/preferences_repository.dart';
+import 'dart:io';
+
+import 'package:dio/dio.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+/// Provide a configured Dio instance (used by data layer)
+final dioProvider = Provider<Dio>((ref) {
+  // baseUrl can be configured via environment; use a sensible default
+  return Dio(BaseOptions(
+    baseUrl: 'https://anyway.anydev.info',
+    connectTimeout: const Duration(seconds: 5),
+    receiveTimeout: const Duration(seconds: 120),
+    headers: {
+      HttpHeaders.acceptHeader: 'application/json',
+      HttpHeaders.contentTypeHeader: 'application/json',
+    },
+  ));
+});
+
+/// Provide a simple wrapper client if needed elsewhere
+final dioClientProvider = Provider<DioClient>((ref) {
+  final dio = ref.read(dioProvider);
+  return DioClient(baseUrl: dio.options.baseUrl);
+});
+
+/// Onboarding repository backed by SharedPreferences
+final onboardingRepositoryProvider = Provider<OnboardingRepository>((ref) {
+  return LocalOnboardingRepository();
+});
+
+/// Preferences repository (local persistence)
+final preferencesRepositoryProvider = Provider<PreferencesRepository>((ref) {
+  return PreferencesRepositoryImpl();
+});
+
+/// Trip repository backed by the backend
+final tripRepositoryProvider = Provider<TripRepository>((ref) {
+  final dio = ref.read(dioProvider);
+  final remote = TripRemoteDataSourceImpl(dio: dio);
+  return BackendTripRepository(remote: remote);
+});