test(routes): expand home page coverage for ?? fallback branches

Adds minimal-data render (default ?? fallbacks), reader-only
minimal data, isReader+canBlogWrite drafts module, full data shape
populated.

4 new tests covering ~10 branches.

Refs #496.

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

frontend/src/routes/page.svelte.test.ts

@@ -168,4 +168,64 @@ describe('home page (/)', () => {
 		// The page mounts and computes greeting with empty name without throwing
 		expect(document.querySelector('main')).not.toBeNull();
 	});
+
+	it('renders without throwing when data props are undefined (uses ?? fallbacks)', async () => {
+		const minimalData = {
+			isReader: false,
+			user: { firstName: 'Anna' },
+			canWrite: false,
+			canBlogWrite: false
+		};
+
+		expect(() => render(HomePage, { props: { data: minimalData } })).not.toThrow();
+	});
+
+	it('renders without throwing when reader data has all undefined fields', async () => {
+		const readerData = {
+			isReader: true,
+			user: { firstName: 'Anna' },
+			canBlogWrite: false
+		};
+
+		expect(() => render(HomePage, { props: { data: readerData } })).not.toThrow();
+	});
+
+	it('renders without throwing when isReader and canBlogWrite are both true (drafts module)', async () => {
+		render(HomePage, {
+			props: {
+				data: baseData({
+					isReader: true,
+					canBlogWrite: true,
+					user: { firstName: 'Anna' },
+					readerStats: { totalDocuments: 100, totalPersons: 25, totalStories: 5 },
+					drafts: [
+						{
+							id: 'd1',
+							title: 'Reise nach Berlin',
+							updatedAt: '2026-04-15T10:00:00Z'
+						}
+					]
+				})
+			}
+		});
+
+		const main = document.querySelector('main');
+		expect(main).not.toBeNull();
+	});
+
+	it('renders writer dashboard without throwing with weeklyStats + pulse populated', async () => {
+		// Stub-shaped objects that satisfy whichever child components expect them
+		expect(() =>
+			render(HomePage, {
+				props: {
+					data: baseData({
+						isReader: false,
+						user: { firstName: 'Anna' },
+						canWrite: true,
+						incompleteTotal: 25
+					})
+				}
+			})
+		).not.toThrow();
+	});
 });