Which component are you using?:
/area vertical-pod-autoscaler

Is your feature request designed to solve a problem? If so describe the problem this feature should solve.:
Currently, VPA validation is implemented programmatically in the admission webhook (pkg/admission-controller/resource/vpa/handler.go). This makes the validation rules less declarative and harder to maintain. CEL validation would provide validation at the API server level before object persistence, improving validation efficiency and maintainability.
Ref: https://kubernetes.io/docs/reference/using-api/cel/

Describe the solution you'd like.:
Moving applicable validations to CEL would align with Kubernetes best practices and provide earlier validation in the request flow.

Describe any alternative solutions you've considered.:

Additional context.:

/assign