This is very cool! I too have been very curious about ATProto after reading Dan Abramov's blog posts on it: https://overreacted.io/a-social-filesystem/

One question, I tried sharing your site with a friend and the share URL is coming up as http://localhost/ which is strange and I've never seen before. Is this something that's possible to customise via meta tag, or is this a bug in my browser (Vanadium 147 on GrapheneOS)?