[Feature] Add Support for Floatplane's New Captions System

[ellierewind]

Floatplane recently introduced a new captions system, moving away from burned-in captions.

Please consider adding support for their closed captions system.

[Inrixia]

Just noting that this is planned, actually was planned since it was announced but since noone had made a issue I completely forgot about it.

I'm sick atm but next time I'm going over open issues etc I'll see about implementing this. I'm hoping that there is a fairly simple api call I can make to just get the file the same way I do for the thumbnails.

Thanks for opening this ❤️