style: 调整二维码尺寸为 240x240，增加容器高度

frontend/src/pages/login/QRCodeLogin.module.css

@@ -13,6 +13,7 @@
   display: flex;
   justify-content: center;
   margin-bottom: 20px;
+  min-height: 260px;
 }
 
 .qrcode svg {

frontend/src/pages/login/QRCodeLogin.tsx

@@ -100,8 +100,8 @@ export default function QRCodeLogin({ visible, onClose }: QRCodeLoginProps) {
             qrObjRef.current = window.QRLogin({
               id: 'feishu-qrcode-container',
               goto: authUrl,
-              width: '200',
+              width: '240',
-              height: '200',
+              height: '240',
             })
           }, 50)