ci: use Headlamp service DNS name for E2E tests

Use the Kubernetes service DNS name (headlamp.kube-system.svc.cluster.local)
instead of ClusterIP for reliable in-cluster DNS resolution.

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>

.github/workflows/e2e.yaml

@@ -31,7 +31,7 @@ jobs:
       - name: Run E2E tests
         run: npm run e2e
         env:
-          HEADLAMP_URL: ${{ secrets.HEADLAMP_URL || 'http://10.43.61.138' }}
+          HEADLAMP_URL: ${{ secrets.HEADLAMP_URL || 'http://headlamp.kube-system.svc.cluster.local' }}
           HEADLAMP_TOKEN: ${{ secrets.HEADLAMP_TOKEN }}
           AUTHENTIK_USERNAME: ${{ secrets.AUTHENTIK_USERNAME }}
           AUTHENTIK_PASSWORD: ${{ secrets.AUTHENTIK_PASSWORD }}