APIs embedding batchv1.JobSpec get rejected due to missing k8s:maxItems implementation

Controller-tools implementing `+k8s:immutable` and not implementing `k8s:maxItems` results in CRDs embedding `batchv1.JobSpec` to get rejected by the apiserver due to exceeding the CEL cost budget with an error like the below:

```
CustomResourceDefinition.apiextensions.k8s.io "clustertrainingruntimes.trainer.kubeflow.org" is invalid:
[spec.validation.openAPIV3Schema.properties[spec].properties[template].properties[spec]
.properties[replicatedJobs].items.properties[template].properties[spec].properties[scheduling]
.properties[resourceClaims].x-kubernetes-validations[0].rule: Forbidden: estimated rule cost
exceeds budget by factor of more than 100x (try simplifying the rule, or adding maxItems,
maxProperties, and maxLength where arrays, maps, and strings are declared),
...
spec.validation.openAPIV3Schema: Forbidden: x-kubernetes-validations estimated rule cost total
for entire OpenAPIv3 schema exceeds budget by factor of more than 100x]
```

Start by tracing controller-tools handling of k8s:immutable and the missing k8s:maxItems implementation, then reproduce the failure with a CRD embedding batchv1.JobSpec. Done means generated CRD schemas include appropriate collection bounds so the apiserver no longer rejects them for exceeding the CEL cost budget.

Written by the indexing model from the issue text.