Spec deltas

The polyfill-connectors package SHALL provide a makeValidateRecord(schemas) helper that takes a stream-keyed registry of zod schemas and returns a ValidateRecord closure with consistent diagnostic shape ({ ok: true, data } on pass; { ok: false, issues: [{ path, message }, ...] } on fail; pass-through { ok: true, data } on unknown stream).

A polyfill connector that has a parsers.ts (or equivalent record-builder layer) and emits at least one stream SHALL ship a schemas.ts declaring zod schemas for every stream it emits, wired into the connector via runConnector({ ..., validateRecord }) (or the equivalent custom emit path for connectors that don't use runConnector).