Schema.Never properties cannot round-trip through JSON Schema

[Chasewhip8]

What version of Effect is running?

4.0.0-rc.112

What steps can reproduce the bug?

import { Schema, SchemaRepresentation } from "effect"

const document = Schema.toJsonSchemaDocument(
  Schema.Struct({ value: Schema.optionalKey(Schema.Never) })
)

SchemaRepresentation.fromJsonSchemaDocument(document)

What is the expected behavior?

Import succeeds. The imported schema accepts {} and rejects any supplied value.

What do you see instead?

Unsupported JSON Schema keyword "not"
  at ["schema"]["properties"]["value"]["not"]

Additional information

The exporter emits { "not": {} }, but the importer rejects it. Replacing that property schema with the equivalent false works.

This also blocks @effect/openapi-generator@4.0.0-rc.112 from reading Effect-generated OpenAPI specs. Related: #7410.