[Feature request] Allow setting of filename

https://github.com/orhun/rustypaste/tree/master?tab=readme-ov-file#override-the-filename-when-using-random_url

I'd like to host a predictably named file, but update it via droidypaste. So, I'd need to be able to specify the URL/filename

Bonus points for a workflow that downloads the named text file into the edit box. :)