docs(requirements): note shared TrackedOperationId model in notification docs

docs/requirements/Component-NotificationService.md

@@ -61,6 +61,7 @@ NotificationStatus status = Notify.Status(id);
 - `Notify.To("listName").Send(...)` is **asynchronous**: it generates a `NotificationId` (GUID) locally, hands the notification to the site Store-and-Forward Engine for forwarding to central, and returns the `NotificationId` to the script **immediately**. The script does not block waiting for delivery.
 - The message body is **plain text** only. No HTML content.
 - `Notify.Status(notificationId)` returns a small **status record** — the current status, retry count, last error, and key timestamps (enqueued, delivered). While the notification is still in the site Store-and-Forward buffer, the site answers the query **locally** with status `Forwarding`; once forwarded to central, the query round-trips to central and reads the `Notifications` table.
+- The returned `NotificationId` is a `TrackedOperationId` — the shared Commons tracking-handle type used by all store-and-forward producers; `NotificationId` is simply the notification-domain name for it. Likewise, `Notify.Status` is a thin alias of the unified `Tracking.Status` accessor, retained for backward compatibility. This is a naming/type clarification only — notification delivery behavior is unchanged.
 
 ## Notification Delivery Behavior