test(web/admin): AdminTabs now has seven tabs (Diagnostics added)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K55iTxn95BtshocgdE1shW

web/src/lib/components/AdminTabs.test.ts

@@ -52,7 +52,7 @@ describe('AdminTabs', () => {
     );
   });
 
-  test('renders all six tabs in order', () => {
+  test('renders all seven tabs in order', () => {
     state.pageUrl = new URL('http://localhost/admin');
     render(AdminTabs);
     const links = screen.getAllByRole('link');
@@ -62,6 +62,7 @@ describe('AdminTabs', () => {
       'Requests',
       'Quarantine',
       'Playback errors',
+      'Diagnostics',
       'Users'
     ]);
   });