style: 更新 QR SDK 配置参数，添加 style 属性

- width/height: 250x250
- style: width:300px;height:270px;border:none

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/login/QRCodeLogin.tsx

@@ -100,8 +100,9 @@ export default function QRCodeLogin({ visible, onClose }: QRCodeLoginProps) {
             qrObjRef.current = window.QRLogin({
               id: 'feishu-qrcode-container',
               goto: authUrl,
-              width: '280',
+              width: '250',
-              height: '280',
+              height: '250',
+              style: 'width:300px;height:270px;border:none'
             })
           }, 50)