feat(09-04): delete AdminView + 4 tab files; update tests + router guard test

- git rm AdminView.vue, AdminUsersTab.vue, AdminQuotasTab.vue, AdminAiConfigTab.vue, AuditLogTab.vue
- Migrate tab tests to import from views/admin/Admin*View.vue
- Update router.guard.test.js: replace AdminView mock with AdminLayout + 5 admin view mocks
- Add D-09 redirect test (admin on / → /admin)
- Fix stale api/admin.js JSDoc consumer list
- Fix SettingsView.vue stale AdminView comment reference

frontend/src/components/admin/__tests__/AdminQuotasTab.test.js

@@ -8,7 +8,7 @@ vi.mock('../../../api/client.js', () => ({
   adminUpdateQuota: vi.fn(),
 }))
 
-import AdminQuotasTab from '../AdminQuotasTab.vue'
+import AdminQuotasTab from '../../../views/admin/AdminQuotasView.vue'
 import * as api from '../../../api/client.js'
 
 const MB = 1048576