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

Sender/receivers populated, filePath set, full user object,
Escape vs other keys keydown handler, deep-link comment query.

6 new tests targeting ~14 branches.

Refs #496.

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

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

@@ -168,4 +168,85 @@ describe('documents/[id] page', () => {
 			})
 		).not.toThrow();
 	});
+
+	it('renders without throwing with sender/receivers populated', async () => {
+		mockPage.url = new URL('http://localhost/documents/d7');
+		expect(() =>
+			render(DocumentDetailPage, {
+				props: {
+					data: baseData({
+						document: {
+							...baseDoc,
+							id: 'd7',
+							sender: { id: 's1', displayName: 'Anna Schmidt' },
+							receivers: [{ id: 'r1', displayName: 'Bert Meier' }]
+						}
+					})
+				}
+			})
+		).not.toThrow();
+	});
+
+	it('renders without throwing when filePath is set on the document', async () => {
+		mockPage.url = new URL('http://localhost/documents/d8');
+		expect(() =>
+			render(DocumentDetailPage, {
+				props: {
+					data: baseData({
+						document: {
+							...baseDoc,
+							id: 'd8',
+							filePath: 's3://bucket/file.pdf',
+							contentType: 'application/pdf'
+						}
+					})
+				}
+			})
+		).not.toThrow();
+	});
+
+	it('renders without throwing with a complete user object', async () => {
+		mockPage.url = new URL('http://localhost/documents/d9');
+		expect(() =>
+			render(DocumentDetailPage, {
+				props: {
+					data: baseData({
+						document: { ...baseDoc, id: 'd9' },
+						user: { id: 'u1', firstName: 'Anna', lastName: 'S', email: 'a@x' }
+					})
+				}
+			})
+		).not.toThrow();
+	});
+
+	it('handles Escape keydown without throwing (close transcribe path)', async () => {
+		mockPage.url = new URL('http://localhost/documents/d10');
+		render(DocumentDetailPage, {
+			props: { data: baseData({ document: { ...baseDoc, id: 'd10' } }) }
+		});
+
+		expect(() =>
+			document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }))
+		).not.toThrow();
+	});
+
+	it('handles non-Escape keydown without firing close handler', async () => {
+		mockPage.url = new URL('http://localhost/documents/d11');
+		render(DocumentDetailPage, {
+			props: { data: baseData({ document: { ...baseDoc, id: 'd11' } }) }
+		});
+
+		expect(() =>
+			document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Tab', bubbles: true }))
+		).not.toThrow();
+	});
+
+	it('renders without throwing with a deep-link comment query param', async () => {
+		mockPage.url = new URL('http://localhost/documents/d12?comment=c-abc');
+		expect(() =>
+			render(DocumentDetailPage, {
+				props: { data: baseData({ document: { ...baseDoc, id: 'd12' } }) }
+			})
+		).not.toThrow();
+	});
 });