mode="array" and iterating over each item, the name field must be a nested item of the array field and cannot simply be the array item's index. (https://github.com/nickhudkins/reimagined-umbrella/blob/main/src/main.tsx#L92). This is somewhat related to type safe SubForms, and the overall form composition story, so it's possible that casting this as any is fine for now and we'll figure out a better API later?