test(subdirectory): close review nits on the navbar-logo round-3 fix

Addresses three minor findings from the /review-code pass on e6a58cb047:

- pathUtils.test.ts: cover `stripAppRoot('/superset/')` (trailing slash)
  in addition to the no-slash variant — both branches now return '/'.
- Menu.test.tsx: wrap the three rooted-brand-path regressions in a
  describe block with a beforeEach that resets `observedGenericLinkTo`,
  so a future inserted test cannot leak stale state.
- Menu.test.tsx: add a regression for the theme.brandLogoHref branch —
  asserts that when `theme.brandLogoUrl` is set and `brandLogoHref` is
  already rooted, the resulting <a href> is single-prefix. Closes the
  test-coverage gap noted by the reviewer (the branch's runtime
  correctness was already covered by ensureAppRoot idempotence in
  e6a58cb047, but had no dedicated test).

71/71 touched-suite Jest tests green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

superset-frontend/src/features/home/Menu.test.tsx

@@ -841,8 +841,12 @@ test('brand link falls back to brand.path when theme brandLogoUrl is absent', as
 // already has the root stripped — the value the production Router will then
 // safely re-prepend.
 
+describe('brand link single-prefix regressions (subdirectory deployment)', () => {
+  beforeEach(() => {
+    observedGenericLinkTo = null;
+  });
+
 test('brand link hands a root-stripped path to GenericLink when brand.path arrives already rooted (SPA route)', async () => {
-  observedGenericLinkTo = null;
   applicationRootMock.mockReturnValue('/superset');
   staticAssetsPrefixMock.mockReturnValue('/superset');
   useSelectorMock.mockReturnValue({ roles: user.roles });
@@ -911,7 +915,6 @@ test('brand link is single-prefix when brand.path arrives already rooted (non-SP
 });
 
 test('brand link strips a nested application root before handing to GenericLink', async () => {
-  observedGenericLinkTo = null;
   applicationRootMock.mockReturnValue('/preset/superset');
   staticAssetsPrefixMock.mockReturnValue('/preset/superset');
   useSelectorMock.mockReturnValue({ roles: user.roles });
@@ -941,3 +944,33 @@ test('brand link strips a nested application root before handing to GenericLink'
   });
   expect(observedGenericLinkTo).toBe('/welcome/');
 });
+
+test('brand link from theme.brandLogoHref is single-prefix when already rooted', async () => {
+  applicationRootMock.mockReturnValue('/superset');
+  staticAssetsPrefixMock.mockReturnValue('/superset');
+  useSelectorMock.mockReturnValue({ roles: user.roles });
+
+  useThemeMock.mockReturnValue({
+    ...CoreTheme.supersetTheme,
+    brandLogoUrl: '/superset/static/assets/images/custom-logo.png',
+    brandLogoHref: '/superset/welcome/',
+  });
+
+  render(<Menu {...mockedProps} />, {
+    useRedux: true,
+    useQueryParams: true,
+    useRouter: true,
+    useTheme: true,
+  });
+
+  const brandLink = await screen.findByRole('link', {
+    name: /apache superset/i,
+  });
+  expect(brandLink).toHaveAttribute('href', '/superset/welcome/');
+  const brandImg = brandLink.querySelector('img');
+  expect(brandImg).toHaveAttribute(
+    'src',
+    '/superset/static/assets/images/custom-logo.png',
+  );
+});
+});

superset-frontend/src/utils/pathUtils.test.ts

@@ -275,6 +275,12 @@ test('stripAppRoot returns "/" when given the bare application root', async () =
   expect(stripAppRoot('/superset')).toBe('/');
 });
 
+test('stripAppRoot returns "/" when given the application root with a trailing slash', async () => {
+  const { stripAppRoot } = await loadPathUtils('/superset/');
+
+  expect(stripAppRoot('/superset/')).toBe('/');
+});
+
 test('stripAppRoot respects segment boundaries — `/supersetfoo` is not the root', async () => {
   const { stripAppRoot } = await loadPathUtils('/superset/');