fix: use "Polaris" as plugin settings display name

Changed from "headlamp-polaris-plugin" to "Polaris" in the
registerPluginSettings call. This makes the plugin name appear
cleanly in Settings > Plugins.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

src/index.tsx

@@ -74,4 +74,4 @@ registerRoute({
   ),
 });
 
-registerPluginSettings('headlamp-polaris-plugin', PolarisSettings, true);
+registerPluginSettings('polaris', PolarisSettings, true);