dev.cocore.app.registration

How an application announces itself to co/core so it can connect users' accounts with one click ("Sign in with co/core"). Published by the application on ITS OWN account (a did:plc or did:web with a repo), one record per DID at rkey `self` — there is no central app registry. When the app calls `dev.cocore.devicePair.start` with `appDid`, the AppView reads this record from the app's PDS: `name` is what the approve screen shows, and `returnUrls` are the only places the approve screen may send the browser afterwards. A return URL is additionally honoured only when its host proves it belongs to this DID by serving `https://<host>/.well-known/cocore-app.json` containing `{"did": "<this DID>"}` — so a record on a stranger's account cannot borrow a real app's domain.