fix: change plugin display name from 'headlamp-polaris-plugin' to 'polaris'

Update package.json name field to show cleaner name in Headlamp Settings → Plugins.

Before: headlamp-polaris-plugin
After: polaris

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

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "headlamp-polaris-plugin",
+  "name": "polaris",
   "version": "0.3.5",
   "description": "Headlamp plugin for Fairwinds Polaris audit results",
   "scripts": {