refactor: move notification domain to lib/notification/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/notification/notifications.spec.ts

@@ -0,0 +1,55 @@
+import { describe, it, expect } from 'vitest';
+import { parseNotificationEvent } from '$lib/notification/notifications';
+
+describe('parseNotificationEvent', () => {
+	const valid = {
+		id: '00000000-0000-0000-0000-000000000001',
+		documentId: '00000000-0000-0000-0000-000000000002',
+		actorName: 'Anna Müller',
+		type: 'MENTION',
+		referenceId: '00000000-0000-0000-0000-000000000003',
+		annotationId: null,
+		read: false,
+		createdAt: '2024-06-15T10:00:00',
+		documentTitle: 'Geburtsurkunde Opa Karl'
+	};
+
+	it('should return parsed object for a valid payload', () => {
+		const result = parseNotificationEvent(JSON.stringify(valid));
+		expect(result).not.toBeNull();
+		expect(result?.id).toBe(valid.id);
+		expect(result?.actorName).toBe('Anna Müller');
+	});
+
+	it('should return null for invalid JSON', () => {
+		expect(parseNotificationEvent('not-json')).toBeNull();
+	});
+
+	it('should return null when id is missing', () => {
+		// eslint-disable-next-line @typescript-eslint/no-unused-vars
+		const { id, ...noId } = valid;
+		expect(parseNotificationEvent(JSON.stringify(noId))).toBeNull();
+	});
+
+	it('should return null when documentId is missing', () => {
+		// eslint-disable-next-line @typescript-eslint/no-unused-vars
+		const { documentId, ...noDocId } = valid;
+		expect(parseNotificationEvent(JSON.stringify(noDocId))).toBeNull();
+	});
+
+	it('should return null when actorName is missing', () => {
+		// eslint-disable-next-line @typescript-eslint/no-unused-vars
+		const { actorName, ...noActor } = valid;
+		expect(parseNotificationEvent(JSON.stringify(noActor))).toBeNull();
+	});
+
+	it('should return null for unknown notification type', () => {
+		expect(parseNotificationEvent(JSON.stringify({ ...valid, type: 'UNKNOWN' }))).toBeNull();
+	});
+
+	it('should accept REPLY as a valid type', () => {
+		const result = parseNotificationEvent(JSON.stringify({ ...valid, type: 'REPLY' }));
+		expect(result).not.toBeNull();
+		expect(result?.type).toBe('REPLY');
+	});
+});