feat: emit raw qrcode code field for client-side QR rendering

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/channel/weixin.js

@@ -312,7 +312,7 @@ async function _runLogin({ callId, timeoutMs, botType, emit, isAborted }) {
     emit({
       action: 'event',
       event:  'qrcode',
-      data:   { url: activeLogin.qrcodeUrl, expire: 30, index: qrRefreshCount },
+      data:   { url: activeLogin.qrcodeUrl, code: activeLogin.qrcode, expire: 30, index: qrRefreshCount },
     });
     log.info('weixin', `callId=${callId} qrcode emitted index=${qrRefreshCount}`);
   }