fix：文件下载预览的实现

src/pages/Chat/components/ChatItem/ChatAnswerAttchment.tsx

@@ -29,7 +29,14 @@ export const ChatAnswerAttachment: React.FC<ChatAnswerAttachmentProps> = ({ answ
     const docId = `${doc.knowledgeName}/${doc.documentStoreKey}`
     const res = await fetchGetDocumentLink(docId)
     if (res.data) {
-      window.open(res.data.docUrl)
+      const link = document.createElement('a')
+      link.href = res.data.docUrl
+      link.target = '_blank'
+      link.rel = 'noopener noreferrer' // 安全考虑
+      link.style.display = 'none'
+      document.body.appendChild(link)
+      link.click()
+      document.body.removeChild(link)
     }
   }
   return (