fix(e2e): use localhost via kubectl port-forward for HEADLAMP_URL

The browser runs outside the cluster and cannot resolve
headlamp-e2e.${E2E_NAMESPACE}.svc.cluster.local DNS names.

- Start kubectl port-forward in background after service rollout
- Poll until localhost:4466 is reachable before writing .env.e2e
- Write HEADLAMP_URL=http://localhost:4466 so Playwright browser can connect
- teardown: kill port-forward processes with pkill

Fixes PRI-752.
Co-Authored-By: Paperclip <noreply@paperclip.ing>

scripts/teardown-e2e-headlamp.sh

@@ -26,5 +26,10 @@ if [ -f "$REPO_ROOT/.env.e2e" ]; then
   echo "Removed .env.e2e"
 fi
 
+echo "Killing any kubectl port-forward processes for ${E2E_RELEASE}..."
+pkill -f "kubectl port-forward.*${E2E_RELEASE}" 2>/dev/null || true
+
+rm -f "$REPO_ROOT/.port-forward.log"
+
 echo ""
 echo "E2E teardown complete."