fix: resolve duplicate background notifications and format contact names in local notification titles

whatsapp_app/lib/services/whatsapp_service.dart

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'package:get/get.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
 import '../config/app_config.dart';
+import 'contacts_service.dart';
 import 'firebase_service.dart';
 
 enum WsStatus { disconnected, connecting, connected, waReady }
@@ -104,9 +105,15 @@ class WhatsAppService extends GetxService {
              body = '📷 Media/Audio message';
           }
           try {
+            final String cleanNumber = chatId?.split('@')[0] ?? '';
+            final String senderName = Get.find<ContactsService>().getContactName(
+              cleanNumber,
+              cleanNumber.isNotEmpty ? '+$cleanNumber' : 'WhatsApp',
+            );
+
             Get.find<FirebaseService>().showLocalNotificationFromData({
               'chatId': chatId,
-              'name': chatId?.split('@')[0] ?? 'WhatsApp',
+              'name': senderName,
               'body': body,
             });
           } catch (e) {