feat(ADM-018): completed feature

project/src/modules/notifications/domain/notification.ts

@@ -0,0 +1,9 @@
+export type EmailTemplate = 'order_confirmation' | 'payment_failed' | 'order_shipped';
+
+export interface EmailMessage {
+  eventId: string;
+  template: EmailTemplate;
+  recipient: string;
+  subject: string;
+  body: string;
+}