fix: resolve error in HTML builder script

[sarahatwork]

Hi! I hope this project is still active - it's pretty neat!

I ran into an error when generating HTML from a Figma file of mine and updated the types/checks accordingly.

Also added public to the .gitignore file to prevent committing generated public files when running yarn watch.

[bernaferrari]

Hey, thanks! Yes, it is alive. It took a long break, but I'm now actively rewriting everything. Thanks for that, I wouldn't catch otherwise.

(I'm not sure if I'll merge yet, but it is more because I'm changing everything, and I'll incorporate your changes in my new codebase)

[sarahatwork]

Sounds good, thanks!