fix: resolve DarwinAudioError on iOS using temporary .mp3 extension and upgrade mock Voice Note base64 to valid silent MP3

whatsapp_app/lib/widgets/message_bubble.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
+import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
 import 'package:get/get.dart';
@@ -210,7 +211,16 @@ class _InteractiveMediaWidgetState extends State<InteractiveMediaWidget> {
         await _player.pause();
       } else {
         final bytes = base64Decode(base64Data);
-        await _player.play(BytesSource(bytes));
+        // Clean special characters from ID to construct a safe filename
+        final safeId = widget.message.id.replaceAll(RegExp(r'[^a-zA-Z0-9]'), '');
+        final tempDir = Directory.systemTemp;
+        final tempFile = File('${tempDir.path}/voice_$safeId.mp3');
+        
+        if (!await tempFile.exists()) {
+          await tempFile.writeAsBytes(bytes);
+        }
+        
+        await _player.play(DeviceFileSource(tempFile.path));
       }
     } catch (e) {
       print('[AUDIO PLAYBACK ERROR] $e');