Integrate PauseNotificationCard into notification feed

Locate the existing notification list item factory — likely a `switch` on `notificationType` string or a `Map` registry. Prefer the map-based registry pattern if it already exists, as it avoids touching a growing switch statement. When parsing the incoming notification payload into `PauseNotificationCardData.fromJson()`, wrap the call in a try/catch and return a `GenericNotificationCard` fallback on parse failure to ensure the feed never crashes on a malformed payload. Confirm with the team whether the role-visibility filter is already applied at the BLoC/repository layer (filtering out non-coordinator notifications before they reach the UI) or whether the UI must apply an additional guard.

Widget test: render the `NotificationFeedList` widget with a mixed list including one `pause_status` item and two other notification types; assert `PauseNotificationCard` appears exactly once and other card types appear with correct counts. Unit test for the factory: assert that `factory.build(type: 'pause_status', data: {...})` returns a `PauseNotificationCard` instance. Regression test: snapshot/golden test of the full notification feed with existing item types to detect unintended rendering changes. Manual QA checklist: coordinator sees pause card, peer mentor does not.