at.rolld.profile

A single per-user record (key 'self') that declares 'this account uses rolld'. Its PRESENCE is the signal that an account participates, so the friends-feed can cheaply find which of a user's follows to fetch (query for this record across follows, then read plays only for those who have it). Its DELETION is a clean opt-out. Holds optional lightweight display preferences; the authoritative bio/avatar still come from app.bsky.actor.profile, not here. Modeled on atmot's stats record doing the same double duty.