Forms with React Hook Form

Description

Build, advise on, and review forms with React Hook Form — useForm setup and defaultValues, register vs Controller for controlled components (Radix/shadcn Select, Checkbox, date pickers, React Native inputs), schema validation with @hookform/resolvers (Zod), typing input vs output, validation modes, field arrays, server errors with setError, submitting to Server Actions/APIs, performance (useWatch, formState subscriptions), and accessibility. Use whenever react-hook-form is installed or the user builds a form, multi-step form, dynamic field list, or asks why a field doesn't register, validation doesn't fire, or the form re-renders too much.