test(documents): expand documents/[id] page coverage

Adds doc.title in document title, originalFilename fallback,
'Dokument' default fallback, canWrite=true render, geschichten +
inferredRelationship rendering, doc.id empty handling, task=transcribe
URL parameter render.

7 new tests targeting ~25 branches.

Refs #496.

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

frontend/src/routes/documents/[id]/page.svelte.test.ts

@@ -91,4 +91,81 @@ describe('documents/[id] page', () => {
 		const stored = localStorage.getItem('familienarchiv.lastVisited');
 		expect(stored).toContain('d1');
 	});
+
+	it('uses doc.title as the document title when set', async () => {
+		mockPage.url = new URL('http://localhost/documents/d1');
+		render(DocumentDetailPage, { props: { data: baseData() } });
+
+		// The browser <title> reflects doc.title when set
+		await new Promise((r) => setTimeout(r, 30));
+		expect(document.title).toContain('Brief an Helene');
+	});
+
+	it('falls back to originalFilename when title is empty', async () => {
+		mockPage.url = new URL('http://localhost/documents/d2');
+		render(DocumentDetailPage, {
+			props: {
+				data: baseData({
+					document: { ...baseDoc, id: 'd2', title: '', originalFilename: 'fallback.pdf' }
+				})
+			}
+		});
+
+		await new Promise((r) => setTimeout(r, 30));
+		expect(document.title).toContain('fallback.pdf');
+	});
+
+	it('falls back to "Dokument" when title and originalFilename are empty', async () => {
+		mockPage.url = new URL('http://localhost/documents/d3');
+		render(DocumentDetailPage, {
+			props: {
+				data: baseData({
+					document: { ...baseDoc, id: 'd3', title: '', originalFilename: '' }
+				})
+			}
+		});
+
+		await new Promise((r) => setTimeout(r, 30));
+		expect(document.title).toContain('Dokument');
+	});
+
+	it('renders without throwing when canWrite is true', async () => {
+		mockPage.url = new URL('http://localhost/documents/d4');
+		expect(() =>
+			render(DocumentDetailPage, { props: { data: baseData({ canWrite: true }) } })
+		).not.toThrow();
+	});
+
+	it('renders without throwing when geschichten and inferredRelationship are set', async () => {
+		mockPage.url = new URL('http://localhost/documents/d5');
+		expect(() =>
+			render(DocumentDetailPage, {
+				props: {
+					data: baseData({
+						geschichten: [{ id: 'g1', title: 'Story', publishedAt: null }],
+						inferredRelationship: { label: 'PARENT_OF', from: 'p1', to: 'p2' },
+						canBlogWrite: true
+					})
+				}
+			})
+		).not.toThrow();
+	});
+
+	it('renders without throwing when doc.id is empty', async () => {
+		mockPage.url = new URL('http://localhost/documents/d-empty');
+		expect(() =>
+			render(DocumentDetailPage, {
+				props: { data: baseData({ document: { ...baseDoc, id: '', title: 'No ID' } }) }
+			})
+		).not.toThrow();
+	});
+
+	it('renders with task=transcribe in the URL without throwing', async () => {
+		mockPage.url = new URL('http://localhost/documents/d6?task=transcribe');
+		expect(() =>
+			render(DocumentDetailPage, {
+				props: { data: baseData({ document: { ...baseDoc, id: 'd6' } }) }
+			})
+		).not.toThrow();
+	});
 });