Limit Nudge Receiver
The "limit reached" nudge — awareness, not force (design guide §1). Foyer never watches the foreground app: when a limited app is launched, an inexact alarm is set for the moment today's remaining budget runs out (no exact-alarm permission, no service). At fire time the receiver re-checks real usage, so leaving the app early means no notification. Hard enforcement stays where it always was: the launch gate.