Defines typed forms with Zod 4 where one z.object schema is the single source of both the TypeScript type and runtime validation, coercing string inputs with z.coerce.number() and resolving error messages through next-intl keys. Use when writing or reviewing a Zod schema, wiring react-hook-form or a Server Action validator, fixing a Select "all" sentinel that fails validation, coercing numeric or date inputs, translating validation messages, or migrating a schema from Zod 3 to Zod 4. Not for DRF-side field validation or the shared client/server contract (see drf-zod-contract), locale message wiring itself (see i18n-rtl), or mutation/query plumbing (see react-query).
