feat: Support podman login for GCR/AR registries and configure runsc gvisor binaries

[anj-s]

Summary

• Added support for authenticating Podman container engine with Google Container Registry (GCR) and Artifact Registry (AR) using host-side docker-credential-gcloud.
• Added runsc (gVisor) binary configuration under ActorTemplate in GKE deployment manifest internal/manifests/ax-deployment2.yaml to ensure proper sandboxing.

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Breaking change

Related Issues

None.

Test Plan

• Manually verified: Used to successfully build and deploy AX server/harness templates onto GKE Substrate.

Notes for Reviewer

• Resolves authentication and runtime configuration failures when running E2E testing on remote GKE clusters using podman and gVisor.

[anj-s]

cc @wjjclaud Can you share how to avoid these changes for an E2E run?

[rakyll]

runsc is no longer supported. Update your Kubernetes cluster with the latest Substrate instead.

[wjjclaud]

cc @wjjclaud Can you share how to avoid these changes for an E2E run?

I added some instructions for how to check the substrate version and do authentications in #158. It might help to avoid some frictions.