I don't think this would be practical for a static site. You still need to maintain a list of followers of your account somewhere and that needs to be dynamic if you want it to work the way people expect it to where they follow you from other instances.

Assuming you kept the @ list of accounts through some other means, if you had your webfinger setup with your public key, you could after creating new content to push up sign the publish events and push them to those followers.

I don't know of anyone doing this though.

I think it was Mark Johnson of the linux matters podcast that was talking about how he's experimenting with integrating his blog with the fedi-verse using aws lambda for the dynamic parts https://linuxmatters.sh/16/

I also read another blog about it a while back, but essentially you have the same issue as comment systems where it can't be static, there needs to be some server component handling the back and forth.