phosphor-shell-notifications

The Phosphor.Notifications toast framework: the transient popups a shell flashes when an app posts a notification. ToastHost stacks them newest-on-top, shows up to maxVisible at once and queues the rest, auto-dismisses each after a timeout that pauses while you hover it, and animates the reflow when one leaves. It owns presentation, queueing, and timing only — notification ingest is a separate concern, and the host feeds toasts in by calling show(), typically wiring phosphor-service-notifications to that call. A seam is left where a rules service can suppress or retime a toast.