The beta ring — early access, one switch per person
Sections now have three visibility states: Off (hidden while being built), Beta (visible to beta users), and On (visible to everyone).
A new Users panel lets each account be flipped into the beta ring with one switch — beta users see new sections early, everyone else sees them when they're ready.
Settings panels tied to a section appear and disappear with it, so nobody sees configuration for features they don't have.