ac7eb0385d
- Updated GetByID methods in user and customer services to return specific "not found" errors for better clarity in error responses. - Modified NotificationResponse structure to include a new Recipient field, allowing for more flexible recipient handling. - Changed CreatedAt and UpdatedAt fields in NotificationResponse to use Unix timestamps (int64) for consistency across the application. - Improved notification retrieval logic to handle potential nil values for user and customer lookups, ensuring robust data handling.