fix: force OSS direct download even when traffic quota is enabled

frontend/app.js

@@ -1549,12 +1549,10 @@ handleDragLeave(e) {
       // 构建文件路径
       const filePath = this.currentPath === '/' ? `/${file.name}` : `${this.currentPath}/${file.name}`;
 
-      const hasDownloadTrafficLimit = Number(this.user?.download_traffic_quota || 0) > 0;
       const canDirectOssDownload = this.storageType === 'oss'
-        && this.user?.oss_config_source !== 'none'
-        && !hasDownloadTrafficLimit;
+        && this.user?.oss_config_source !== 'none';
 
-      // OSS 且未启用下载限流：优先使用 OSS 直连下载（速度更快）
+      // OSS 下载优先使用直连（避免服务器中转导致带宽与费用双重损耗）
       if (canDirectOssDownload) {
         const directResult = await this.downloadFromOSS(filePath);
         if (directResult) {