usePgForm

Mount the form store entry and get back the imperative formApi plus generateFormProps for rendering.

Content coming soon. Outline:

Signature: usePgForm(fields, options) → { formApi, generateFormProps, … }
Options: pgFormId, validationMode, revalidationMode, persist, listeners, onSubmit, onSubmitError, afterSubmit
What's captured once vs. what stays live across renders