Gate Layer 2 on healthy k3s networking

[waqasm86]

Summary:

• update the Layer 1 Go dependency to the audited validation commit
• gate Layer 2 preflight on a current k3s node address and healthy GPU Operator pods
• record current upstream chart and image versions with a staged migration recommendation

Dependency:

• review and merge the linked k3s-nvidia-edge validation change before this pull request

Validation:

• gofmt and module verification
• unit and race tests
• go vet, builds, and govulncheck
• Helm dependency build and lint
• default, CPU, local, GeForce, and full-NVIDIA renders
• GitHub Actions helm-validate: success