Introducing 'Fedi Follow Catch'

I’ve got two separate social graphs right now — one on Bluesky, one on Mastodon — and no real sense of how much they overlap. I follow people on one who I probably also want to follow on the other, but I had no way of seeing the gap. So I asked Claude Code to help me figure out a way to actually see it: compare both follow lists and surface who I was missing on each side.