KubernetesObjectApi drops `x-kubernetes-preserve-unknown-fields` when given a plain YAML object

[0x5457]

Describe the bug
KubernetesObjectApi.create() silently drops the CRD schema extension x-kubernetes-preserve-unknown-fields when given a plain JavaScript object parsed from YAML.

Client Version
1.4.0

Server Version
1.34

To Reproduce

const yaml = require("js-yaml");
const k8s = require("@kubernetes/client-node");

async function main() {
  const crd = yaml.load(`
apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  name: foos.example.com
spec:
  group: example.com
  scope: Namespaced
  names:
    plural: foos
    singular: foo
    kind: Foo
  versions:
    - name: v1
      served: true
      storage: true
      schema:
        openAPIV3Schema:
          type: object
          properties:
            spec:
              type: object
              properties:
                podTemplate:
                  type: object
                  x-kubernetes-preserve-unknown-fields: true
`);
  const kc = new k8s.KubeConfig();
  kc.loadFromDefault();
  kc.setCurrentContext("orbstack");
  const client = k8s.KubernetesObjectApi.makeApiClient(kc);

  const result  = await client.create(crd);
  console.log(result.body)
}

main().then(() => console.log("done"));

the API server response does not contain x-kubernetes-preserve-unknown-fields.

Expected behavior
The API server response should retain x-kubernetes-preserve-unknown-fields: true, since it is present in the YAML input.

Example Code
Code snippet for what you are doing

Environment (please complete the following information):

• OS: [macOS]
• Node.js version [26.5.0]

[brendandburns]

js-yaml doesn't know anything about Kubernetes schemas so it can't match the field name with dashes to the corresponding field value (with underscores).

Can you try yaml.loadYaml(...) from yaml.ts and see if that works, that one is typed and stands a better chance, but I'm still not sure if the YAML parser is smart enough to match up since the field names are different (because hyphen is not a valid identifier in TS)