fix(notification): add role=link and touch target to view-all button

- role="link" restores screen reader link semantics (Leonie blocker)
- min-h-[44px] px-1 meets WCAG 2.2 §2.5.8 and our 44×48px target size
- Comment in handleViewAll explains close-before-navigate ordering
- Tests updated to getByRole('link') + new call-order assertion

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

frontend/src/lib/notification/NotificationDropdown.svelte.test.ts

@@ -159,7 +159,7 @@ describe('NotificationDropdown', () => {
 		expect(onMarkAllRead).toHaveBeenCalledOnce();
 	});
 
-	it('calls onClose when the view-all button is clicked', async () => {
+	it('calls onClose when the view-all link is clicked', async () => {
 		const onClose = vi.fn();
 		render(NotificationDropdown, {
 			props: {
@@ -170,12 +170,12 @@ describe('NotificationDropdown', () => {
 			}
 		});
 
-		await page.getByRole('button', { name: /alle aktivitäten|view all/i }).click();
+		await page.getByRole('link', { name: /alle aktivitäten|view all/i }).click();
 
 		expect(onClose).toHaveBeenCalledOnce();
 	});
 
-	it('navigates to /aktivitaeten when the view-all button is clicked', async () => {
+	it('navigates to /aktivitaeten when the view-all link is clicked', async () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [],
@@ -185,11 +185,29 @@ describe('NotificationDropdown', () => {
 			}
 		});
 
-		await page.getByRole('button', { name: /alle aktivitäten|view all/i }).click();
+		await page.getByRole('link', { name: /alle aktivitäten|view all/i }).click();
 
 		expect(goto).toHaveBeenCalledWith('/aktivitaeten');
 	});
 
+	it('calls onClose before navigating to /aktivitaeten', async () => {
+		const callOrder: string[] = [];
+		const onClose = vi.fn(() => callOrder.push('close'));
+		(goto as ReturnType<typeof vi.fn>).mockImplementation(() => callOrder.push('goto'));
+		render(NotificationDropdown, {
+			props: {
+				notifications: [],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose
+			}
+		});
+
+		await page.getByRole('link', { name: /alle aktivitäten|view all/i }).click();
+
+		expect(callOrder).toEqual(['close', 'goto']);
+	});
+
 	it('renders MENTION items with the mention verb text', async () => {
 		render(NotificationDropdown, {
 			props: {