Refactor signup page to use BLoC pattern and implement authentication repository

- Updated signup.dart to replace Provider with BLoC for state management.
- Created AuthRepository to handle authentication logic and Firestore user management.
- Added TripRepository and UserRepository for trip and user data management.
- Implemented methods for user sign-in, sign-up, and data retrieval in repositories.
- Enhanced trip management with create, update, delete, and participant management functionalities.
- Updated AuthService to include new methods for sign-in and sign-up.
- Removed unnecessary print statements from TripService for cleaner code.
- Added dependencies for flutter_bloc and equatable in pubspec.yaml.

Not tested yet

lib/repositories/user_repository.dart

@@ -0,0 +1,95 @@
+import 'package:cloud_firestore/cloud_firestore.dart';
+import '../data/models/user.dart';
+import '../services/auth_service.dart';
+
+class UserRepository {
+  final FirebaseFirestore _firestore;
+  final AuthService _authService;
+
+  UserRepository({
+    FirebaseFirestore? firestore,
+    AuthService? authService,
+  })  : _firestore = firestore ?? FirebaseFirestore.instance,
+        _authService = authService ?? AuthService();
+
+  // Récupérer un utilisateur par ID
+  Future<User?> getUserById(String uid) async {
+    try {
+      final doc = await _firestore.collection('users').doc(uid).get();
+      if (doc.exists) {
+        final data = doc.data() as Map<String, dynamic>;
+        return User.fromMap({...data, 'id': uid});
+      }
+      return null;
+    } catch (e) {
+      throw Exception('Erreur lors de la récupération de l\'utilisateur: $e');
+    }
+  }
+
+  // Récupérer un utilisateur par email
+  Future<User?> getUserByEmail(String email) async {
+    try {
+      final querySnapshot = await _firestore
+          .collection('users')
+          .where('email', isEqualTo: email.trim())
+          .limit(1)
+          .get();
+
+      if (querySnapshot.docs.isNotEmpty) {
+        final doc = querySnapshot.docs.first;
+        final data = doc.data();
+        return User.fromMap({...data, 'id': doc.id});
+      }
+      return null;
+    } catch (e) {
+      throw Exception('Erreur lors de la recherche de l\'utilisateur: $e');
+    }
+  }
+
+  // Mettre à jour un utilisateur
+  Future<bool> updateUser(User user) async {
+    try {
+      await _firestore.collection('users').doc(user.id).update(user.toMap());
+      
+      // Mettre à jour le displayName dans Firebase Auth
+      await _authService.updateDisplayName(displayName: user.fullName);
+      
+      return true;
+    } catch (e) {
+      throw Exception('Erreur lors de la mise à jour: $e');
+    }
+  }
+
+  // Supprimer un utilisateur
+  Future<bool> deleteUser(String uid) async {
+    try {
+      await _firestore.collection('users').doc(uid).delete();
+      // Note: Vous devrez également supprimer le compte Firebase Auth
+      return true;
+    } catch (e) {
+      throw Exception('Erreur lors de la suppression: $e');
+    }
+  }
+
+  // Changer le mot de passe
+  Future<bool> changePassword({
+    required String currentPassword,
+    required String newPassword,
+  }) async {
+    try {
+      final currentUser = _authService.currentUser;
+      if (currentUser?.email == null) {
+        throw Exception('Utilisateur non connecté ou email non disponible');
+      }
+      
+      await _authService.resetPasswordFromCurrentPassword(
+        email: currentUser!.email!,
+        currentPassword: currentPassword,
+        newPassword: newPassword,
+      );
+      return true;
+    } catch (e) {
+      throw Exception('Erreur lors du changement de mot de passe: $e');
+    }
+  }
+}