Module notification 

Structured Notification Sheets and Modal Alert Queue.

Provides NotificationSheetWidget (modal alert with actions and countdown progress) and NotificationQueue (deterministic fixed-capacity notification manager).

Structs

NotificationAction

Action button choice attached to a notification.

NotificationError

Error indicating notification actions capacity exceeded.

NotificationSheetWidget

Modal Notification Sheet widget displaying heads-up alerts, actions, and auto-dismiss progress.

Enums

NotificationPriority

Priority severity of a notification alert.