Copying thumbnails causes OS error 1 over SMB

[DrowningWhale]

Hi,
I'm running red_oxide v0.8.2 on WSL Ubuntu with a SMB share drive mounted. All of my directories are on the shared drive.
The transcoding finishes on all of the files, but the program stops with OS error 1.
I have identified that fs::copy in src/transcode/util.rs is causing the error when it tries to copy the thumbnail to the new transcoded folder.
Using a drop-in copy function from ChatGPT that doesn't use fs::copy works, but I'm not sure how you would want to fix it. I can do a PR with the change that works for me if you would like.

Thanks!