Error Handling

MLForm separates validation errors from submit errors.

Error	Cause
ValidationError	Submit attempted while the form is invalid.
SubmitError	Transport failed or backend returned an error.
SubmissionAbortedError	Submit was aborted by unmount, reset, or explicit abort.
RegistryError	Unknown field/report kind or duplicate registration.

The default transport uses backend { "message": "..." } payloads when available.

{
  "message": "Model is temporarily unavailable."
}

Report payload failures are report-local: a single report can enter an error state without making the whole submit fail. Use this when multiple reports are resolved from one backend response.