概要
This skill provides specialized guidance for developing glanceable system extensions across the Apple ecosystem, including Home Screen widgets, Lock Screen Live Activities, and Control Center interactions. It shifts the developer mental model from 'running apps' to 'archived snapshots,' offering deep expertise in TimelineProvider logic, App Group data sharing, and background refresh budgets. By enforcing strict adherence to sandbox constraints and memory limits, it helps developers avoid common pitfalls like stale data, unresponsive controls, and silent crashes caused by exceeding the 4KB Live Activity data limit.