Cuukit Screen Lid

You start something long — an agent working through a task, a build, a render — and then you cannot leave the desk. Lock the Mac and the screen goes with it: Chrome marks every tab hidden, so work that depends on a page still rendering slows or stops. Leave it unlocked and the room reads your work. Cuukit covers every display behind a 4-digit PIN instead. What was running underneath carries on, the Mac stays awake, and only the PIN gets through. Free, Apple silicon, no account, no network.