feat: add gitops gpu e2e smoke

[skel84]

Summary

• add a dedicated Argo-managed gpu-e2e staging app
• persist the namespace, DeviceClass, Kueue queue objects, and a periodic CronJob smoke
• keep the smoke GPU-only to match the current staging ClusterQueue contract and use the live DRA driver selector

Validation

• kubectl apply --dry-run=server -k kubernetes/apps/gpu-e2e/gpu-e2e
• kubectl apply --dry-run=server -f kubernetes/argo/apps/gpu-e2e/gpu-e2e.yaml
• kubectl apply -k kubernetes/apps/gpu-e2e/gpu-e2e
• kubectl apply -f kubernetes/argo/apps/gpu-e2e/gpu-e2e.yaml
• kubectl create job --from=cronjob/gpu-e2e-direct-smoke gpu-e2e-gitops-smoke-201517
• verified admission -> lease -> claim injection -> pod completion after resetting and reseeding staging allocdb