请求支持 FebBox 跨盘复制

### Please make sure of the following things

- [x] I have read the [documentation](https://alist.nn.ci).
- [x] I'm sure there are no duplicate issues or discussions.
- [x] I'm sure this feature is not implemented.
- [x] I'm sure it's a reasonable and popular requirement.

### Description of the feature / 需求描述

如题。

### Suggested solution / 实现思路

FebBox 的上传 API 是通过离线下载的思路实现的，所以对于其他网盘复制到 FebBox 的请求，可以直接传其他网盘的文件直链作为参数。甚至不需要向本地下载。

### Additional context / 附件

_No response_