notification_count (optional, int): Maximum number of notifications to retrieve (default: 25).
after (optional, str, ISO8601): Fetch notifications newer than this timestamp (for polling).
before (optional, str, ISO8601): Fetch notifications older than this timestamp (for "View More").
200 OK: List of serialized notifications with count.
400 Bad Request: If versioning fails or invalid query parameters are passed.
404 Not Found: If no notifications are found.
500 Internal Server Error: On unhandled exceptions.