feat: complete interactive audio player, contact resolver, unread clearance, and media sending

whatsapp_app/lib/services/whatsapp_service.dart

@@ -218,6 +218,16 @@ class WhatsAppService extends GetxService {
   Future<Map<String, dynamic>> getMedia(String messageId) =>
       _request({ 'type': 'get_media', 'messageId': messageId });
 
+  Future<Map<String, dynamic>> sendMedia(String chatId, String base64, String mimetype, String filename, {String? caption}) =>
+      _request({
+        'type': 'send_media',
+        'chatId': chatId,
+        'base64': base64,
+        'mimetype': mimetype,
+        'filename': filename,
+        'caption': caption ?? ''
+      });
+
   // Cache downloaded media: messageId -> base64
   final RxMap<String, String> mediaCache = <String, String>{}.obs;