I'm a bit late, but you can copy-paste the files in your "browser" folder in your "docs" folder manually, but it's a bit cumbersome.
For one of my project hosted on Github page, I have coded some pre/post scripts that do this automatically when I build the app.
If it can help, the scripts are here: https://github.com/Ant1Braun/rpg/tree/main/scripts
And the pre/post builds should be added in package.json.

Best regards