🌱 Enable optionalorrequired linter

[moko-poi]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

This PR enables the KAL (Kube-API-Linter) optionalorrequired linter, which ensures that every field in API types is explicitly marked as either +optional or +required.

Changes made:

• Enabled optionalorrequired linter in .golangci-kal.yml
• Added +optional markers to fields with omitempty json tags
• Added +required markers to fields without omitempty json tags
• Fixed 1509 linter issues across 148 files

This improves API documentation clarity by making it explicit whether each field is required or optional, following Kubernetes API conventions. This helps API consumers better understand the contract of each field.

Which issue(s) this PR fixes:
Fixes #5491

Special notes for your reviewer:

The changes were made using a combination of automatic fixes (make lint-api-fix) and a custom Python script to handle the remaining cases. The script adds markers based on the presence of omitempty in json tags:

• Fields with json:"...,omitempty" → // +optional
• Fields with json:"..." (no omitempty) → // +required

All changes are purely additive comments and do not affect runtime behavior. Tests pass successfully.

Checklist:

• squashed commits
• includes documentation (N/A - documentation is in code comments)
• includes emoji in title
• adds unit tests (N/A - existing tests validate the changes)
• adds or updates e2e tests (N/A - no behavioral changes)

Release note:

Enabled optionalorrequired linter to improve API documentation clarity by explicitly marking all struct fields as +optional or +required

[k8s-ci-robot]

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[k8s-ci-robot]

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[k8s-ci-robot]

Hi @moko-poi. Thanks for your PR.

I'm waiting for a github.com member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.