Add Zod/Yup style API about form-state HOT 2 CLOSED

Do we want to support Truss-style paren-less syntax? I.e.:

const formConfig = f.object({
  firstName: f.string.required,
  lastName: f.string,
  middle: f.string.requiredWith("Custom message"),
});

I.e. we'd have both required-if-no-opts and requiredWith-if-opts, since in JS we need to know ahead of time what is a field and what is a method.

from form-state.

We've got the start of this

from form-state.