refactor(KnowledgeManagement): 优化知识集详情页面文件记录渲染逻辑

- 将重复的条件判断提取为变量 isFileRecord
- 使用立即执行函数简化 JSX 结构
- 统一文件类型记录的操作按钮渲染方式
- 提高代码可读性和维护性

frontend/src/pages/KnowledgeManagement/Detail/KnowledgeSetDetail.tsx

@@ -335,8 +335,13 @@ const KnowledgeSetDetail = () => {
               />
             </Tooltip>
           )}
-          {(record.contentType === KnowledgeContentType.FILE ||
+          {(() => {
-            record.sourceType === KnowledgeSourceType.FILE_UPLOAD) && (
+            const isFileRecord =
+              record.contentType === KnowledgeContentType.FILE ||
+              record.sourceType === KnowledgeSourceType.FILE_UPLOAD;
+            return (
+              <>
+                {isFileRecord && (
                   <Tooltip title="预览">
                     <Button
                       type="text"
@@ -347,8 +352,7 @@ const KnowledgeSetDetail = () => {
                     />
                   </Tooltip>
                 )}
-          {(record.contentType === KnowledgeContentType.FILE ||
+                {isFileRecord && (
-            record.sourceType === KnowledgeSourceType.FILE_UPLOAD) && (
                   <Tooltip title="下载文件">
                     <Button
                       type="text"
@@ -358,6 +362,7 @@ const KnowledgeSetDetail = () => {
                     />
                   </Tooltip>
                 )}
+                {isFileRecord && (
                   <Button
                     type="text"
                     icon={<EditOutlined />}
@@ -368,8 +373,16 @@ const KnowledgeSetDetail = () => {
                       });
                       setItemEditorOpen(true);
                     }}
-            disabled={isReadOnly || record.rawStatus === KnowledgeStatusType.ARCHIVED || record.rawStatus === KnowledgeStatusType.DEPRECATED}
+                    disabled={
+                      isReadOnly ||
+                      record.rawStatus === KnowledgeStatusType.ARCHIVED ||
+                      record.rawStatus === KnowledgeStatusType.DEPRECATED
+                    }
                   />
+                )}
+              </>
+            );
+          })()}
           <Button
             type="text"
             danger