Bluesky => AP: custom usernames in handles

[snarfed]

Some people who bridge a Bluesky account into the fediverse would like to use their own domain for the handle (#1150), eg @[email protected] instead of @[email protected]. Some of those people would like to go further and choose their username too, eg @[email protected].

We technically support this for web => fediverse right now, https://fed.brid.gy/docs#different+username , but it's been a bit brittle and problematic over time. Still, we could extend it to Bluesky => fediverse.

The key question is how a Bluesky acount would set their custom username. From https://github.com/snarfed/bridgy-fed/issues/1150#issuecomment-2219149924 :

Agreed. Bio is awkward and annoying, DNS or HTTP is inaccessible, authed UI is a burden on my end. I haven't heard a good easy (or at least not hard) answer yet. 🤷

cc @frncs-eu @elfprince13