PWA adaptation

[limdingwen]

Other feature request

Is your feature request related to a problem? Please describe.
I'm quite glad to see that this exists! However, I think currently it's not very user friendly.

Describe the solution you'd like
Ever since #22, there's been development in the Python-in-Browser world. https://pyscript.net/ is one that I'm trying out currently. My intention is to make a very simple PWA where you can just drag-and-drop upload a file, then it auto-downloads the resulting YNAB CSV.

No back end should be necessary, if all goes well.

Describe alternatives you've considered
#22 is a great suggestion. Do y'all think this is a better path?

Another way is to use something like Gooey to make a very simple Python GUI. I don't think most people nowadays install simple desktop tools, though.

Additional context
This is half feature request, half "hey I'm working on this rn, just putting it out there to see if y'all are interested in it" sort of thing.

[nocalla]

Sounds cool and interesting - keep us posted!