test(journey-editor): verify liveAnnounce region clears after 500ms

A persistent non-empty aria-live region can cause stale re-announcements
on adjacent DOM mutations. This test confirms the region is empty after
the 500ms clear timeout fires following a move operation.

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

frontend/src/lib/geschichte/JourneyEditor.svelte.spec.ts

@@ -280,6 +280,36 @@ describe('JourneyEditor — reorder via move buttons', () => {
 	});
 });
 
+describe('JourneyEditor — live announce region', () => {
+	it('clears the live announce region 500ms after a move operation', async () => {
+		const items = [
+			{ id: 'i1', position: 0, document: docSummary('d1', 'Brief A') },
+			{ id: 'i2', position: 1, document: docSummary('d2', 'Brief B') }
+		];
+		vi.stubGlobal(
+			'fetch',
+			vi.fn().mockResolvedValue({
+				ok: true,
+				json: vi.fn().mockResolvedValue([
+					{ id: 'i2', position: 0, document: docSummary('d2', 'Brief B') },
+					{ id: 'i1', position: 1, document: docSummary('d1', 'Brief A') }
+				])
+			})
+		);
+
+		render(JourneyEditor, defaultProps({ geschichte: makeGeschichte({ items }) }));
+
+		await userEvent.click(page.getByRole('button', { name: /Brief B.*nach oben verschieben/ }));
+		await new Promise((r) => setTimeout(r, 50)); // wait for csrfFetch
+
+		const liveRegion = document.querySelector('[aria-live="polite"]');
+		expect((liveRegion?.textContent ?? '').trim().length).toBeGreaterThan(0);
+
+		await new Promise((r) => setTimeout(r, 650)); // 500ms clear timeout + buffer
+		expect((liveRegion?.textContent ?? '').trim()).toBe('');
+	});
+});
+
 describe('JourneyEditor — duplicate document aria-disabled', () => {
 	it('already-added document appears as aria-disabled in picker', async () => {
 		const items = [{ id: 'i1', position: 0, document: docSummary('d1', 'Brief von Karl') }];