test(routes): hit truthy/falsy data.X || '' branches in documents page

Adds two tests that pass all filter props as truthy and as falsy
defaults, covering the seed-from-data-or-default branches.

2 new tests covering ~14 branches (all data.X || '' chains).

Refs #496.

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

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

@@ -285,4 +285,55 @@ describe('documents/+ page', () => {
 			})
 		).not.toThrow();
 	});
+
+	it('renders without throwing with every filter set to a truthy value', async () => {
+		// This hits every "data.X || ''" truthy branch on lines 19-34 of +page.svelte.
+		expect(() =>
+			render(DocumentsListPage, {
+				props: {
+					data: baseData({
+						q: 'brief',
+						from: '1899-01-01',
+						to: '1950-12-31',
+						senderId: 'p-sender',
+						receiverId: 'p-receiver',
+						initialSenderName: 'Anna',
+						initialReceiverName: 'Bert',
+						tags: ['Familie'],
+						sort: 'TITLE',
+						dir: 'asc',
+						tagQ: 'Bri',
+						tagOp: 'OR',
+						zoomFrom: '1900-01-01',
+						zoomTo: '1940-12-31'
+					})
+				}
+			})
+		).not.toThrow();
+	});
+
+	it('renders without throwing with every filter at its falsy default', async () => {
+		expect(() =>
+			render(DocumentsListPage, {
+				props: {
+					data: baseData({
+						q: '',
+						from: '',
+						to: '',
+						senderId: '',
+						receiverId: '',
+						initialSenderName: '',
+						initialReceiverName: '',
+						tags: [],
+						sort: '',
+						dir: '',
+						tagQ: '',
+						tagOp: 'AND',
+						zoomFrom: null,
+						zoomTo: null
+					})
+				}
+			})
+		).not.toThrow();
+	});
 });