fix: strengthen visible content accessibility proof

tests/browser/keyboard.spec.ts

@@ -1,4 +1,4 @@
-import { expect, test } from '../helpers/serve-dist';
+import { expect, expectInsetFocusIndicator, test } from '../helpers/serve-dist';
 
 const navHrefs = [
   '#start',
@@ -94,7 +94,7 @@ test('activating the skip link focuses the visible unobscured portfolio content'
     'tabindex',
     '-1',
   );
-  await assertVisibleUnobscuredFocus(page);
+  await expectInsetFocusIndicator(page, '#portfolio-content');
 });
 
 test('explicit section activation scrolls to and focuses its heading', async ({