fix(MOB): 다운로드 완료 BroadcastReceiver 수신 안 되는 문제 수정

Android 13+ 시스템 브로드캐스트(ACTION_DOWNLOAD_COMPLETE) 수신을 위해
RECEIVER_NOT_EXPORTED → RECEIVER_EXPORTED로 변경

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

android/app/src/main/java/com/codebridgex/webapp/AppUpdateChecker.java

@@ -171,9 +171,10 @@ public class AppUpdateChecker {
         };
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            // DownloadManager 브로드캐스트는 시스템에서 발송하므로 RECEIVER_EXPORTED 필요
             activity.registerReceiver(receiver,
                     new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE),
-                    Context.RECEIVER_NOT_EXPORTED);
+                    Context.RECEIVER_EXPORTED);
         } else {
             activity.registerReceiver(receiver,
                     new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));