v1.14.0 — schema enum/nullable/default builders

Added

• s.enum, s.nullable, s.default, and s.literal schema builders. The
  s helper can now express value-level facets that previously had nowhere to
  live in a SchemaNode:

  defineRoute(handler, {
    request: {
      body: s.object({
        role:   s.enum(['admin', 'user', 'guest']),
        status: s.nullable(s.enum(['active', 'inactive'])),
        limit:  s.default(s.number(), 20),
        kind:   s.literal('user'),
      }),
    },
  });

  These flow through to the exported OpenAPI document, the docs UI schema tree,
  and every request example (Copy as cURL, Postman export, mock server).

Fixed

• defineRoute now emits enum and nullable. SchemaNode could only
  carry type / properties / items / optional, so enum members and
  nullability were dropped before reaching the OpenAPI export or docs UI —
  z.enum([...]) collapsed to a bare string and .nullable() was demoted to
  optional. Both the s builder and the Zod converter now preserve them, and
  the exporter emits enum plus OpenAPI 3.1 type: [<type>, 'null'].

• Default values are now applied in request examples. A schema default
  (via s.default(...) or Zod .default(...)) is emitted to OpenAPI and seeds
  the generated request bodies and query parameters used by Copy as cURL, the
  Postman export, and the mock server. Fields with a default are treated as
  optional and excluded from required.