fix: badge navigation uses window.location.pathname for cluster extraction

* fix: badge navigation uses window.location + correct settings plugin name

- AppBarScoreBadge: Read cluster from window.location.pathname instead of
  useCluster() (returns null in AppBar context) or useLocation() (may not
  reflect cluster prefix outside cluster route context)
- registerPluginSettings: Use 'polaris' to match the deployed directory name
  (plugin is at static-plugins/polaris, not headlamp-polaris)
- Add unit test for no-cluster fallback navigation

Supersedes the source-code fixes from PR #55 without the workflow/deploy
script changes that broke CI.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

* fix: use Object.defineProperty for window.location in test

Replace `as Location` cast with Object.defineProperty to match the
existing beforeEach pattern and fix TypeScript strict mode error.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

---------

Co-authored-by: Gandalf the Greybeard <gandalf@privilegedescalation.dev>
Co-authored-by: Paperclip <noreply@paperclip.ing>

src/index.tsx

@@ -99,7 +99,7 @@ registerRoute({
 });
 
 // Register plugin settings
-registerPluginSettings('headlamp-polaris', PolarisSettings, true);
+registerPluginSettings('polaris', PolarisSettings, true);
 
 // Register details view section for supported controller types
 registerDetailsViewSection(({ resource }) => {