Feature Request: Support volumeClaimTemplates in SandboxTemplate / SandboxClaim

[panchalravi]

Currently, it is possible to create a Sandbox with a PersistentVolume using volumeClaimTemplates directly on the Sandbox spec.

For example:

apiVersion: agents.x-k8s.io/v1alpha1
kind: Sandbox
metadata:
  name: my-sandbox
spec:
  podTemplate:
    spec:
      containers:
        - name: app
          image: ghcr.io/example/agent:latest
          volumeMounts:
            - name: data
              mountPath: /data
  volumeClaimTemplates:
    - metadata:
        name: data
      spec:
        accessModes: ["ReadWriteOnce"]
        resources:
          requests:
            storage: 10Gi
        storageClassName: standard

This ensures that the sandbox gets its own persistent volume backed by a PVC created from the template.

However, creating sandboxes using SandboxClaim and SandboxTemplate does not currently support volumeClaimTemplates on the SandboxTemplate.

Allow SandboxTemplate.spec.podTemplate.spec.volumes to accept a volumeClaimTemplates, mirroring the schema and behavior of Sandbox.spec.volumeClaimTemplates so that each sandbox created via a SandboxClaim from that template will get its own PVC and associated persistent volume.

[vicentefb]

/assign @vicentefb