feat: Implement account management functionality with loading, creation, and error handling

lib/repositories/account_repository.dart

@@ -103,15 +103,44 @@ class AccountRepository {
     return await _firestore.collection('accounts').doc(accountId).get();
   }
 
-  Future<void> createAccount(Map<String, dynamic> accountData) async {
-    await _firestore.collection('accounts').add(accountData);
+  Future<void> updateAccount(String accountId, Account account) async {
+    try {
+      await _firestore.collection('accounts').doc(accountId).update(account.toMap());
+    } catch (e) {
+      _errorService.logError('account_repository.dart', 'Erreur lors de la mise à jour du compte: $e');
+    }
   }
 
-  Future<void> updateAccount(String accountId, Map<String, dynamic> accountData) async {
-    await _firestore.collection('accounts').doc(accountId).update(accountData);
+  Future<void> deleteAccount(String tripId) async {
+    try {
+      final querySnapshot = await _firestore
+          .collection('accounts')
+          .where('tripId', isEqualTo: tripId)
+          .get();
+      if (querySnapshot.docs.isEmpty) {
+        throw Exception('Aucun compte trouvé pour ce voyage');
+      }
+
+      final docId = querySnapshot.docs.first.id;
+
+      final membersSnapshot = await _membersCollection(docId).get();
+      for (var memberDoc in membersSnapshot.docs) {
+        await _membersCollection(docId).doc(memberDoc.id).delete();
+      }
+      await _accountCollection.doc(docId).delete();
+    } catch (e) {
+      _errorService.logError('account_repository.dart', 'Erreur lors de la suppression du compte: $e');
+    }
   }
 
-  Future<void> deleteAccount(String accountId) async {
-    await _firestore.collection('accounts').doc(accountId).delete();
+  Stream<List<GroupMember>> watchGroupMembers(String accountId) {
+    return _membersCollection(accountId).snapshots().map(
+          (snapshot) => snapshot.docs
+              .map((doc) => GroupMember.fromMap(
+                    doc.data() as Map<String, dynamic>,
+                    doc.id,
+                  ))
+              .toList(),
+        );  
   }
 }