test(documents): replace 1 setTimeout sleep in bulk-edit page with vi.waitFor

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/routes/documents/bulk-edit/page.svelte.test.ts

@@ -30,10 +30,7 @@ describe('documents/bulk-edit page', () => {
 	it('redirects to /documents when no documents are selected', async () => {
 		render(BulkEditPage, { props: {} });
 
-		// onMount runs immediately — give it a tick
-		await new Promise((r) => setTimeout(r, 50));
-
-		expect(gotoSpy).toHaveBeenCalledWith('/documents');
+		await vi.waitFor(() => expect(gotoSpy).toHaveBeenCalledWith('/documents'));
 	});
 
 	it('shows the loading spinner while fetching batch metadata', async () => {