Response envelope

The versioned wrapper the CLI's --json mode, MCP tool responses, and noggin-rpc verb responses share. Same shape everywhere so downstream consumers pattern-match once:

{
  status: 'ok' | 'error',
  envelopeVersion: number,      // RESPONSE_ENVELOPE_VERSION
  verb: string | null,
  data?: <verb result>,         // when status === 'ok'
  error?: {
    code: NogginErrorCode | string,
    message: string,
    exitCode: number,
    data?: NogginErrorData,
  },                            // when status === 'error'
}

Two pages:

• JsonEnvelope — the type union plus its two constituent shapes (SuccessEnvelope, ErrorEnvelope).
• Envelope helpers — formatSuccess() and formatError(). Use these instead of building the envelope by hand; they stamp the version field for you and unwrap engine NogginErrors into the wire payload.

Versioning

The envelope version increments only when the wrapper's shape changes (a new field on the error side, a rename, etc.). It's completely independent of SCHEMA_VERSION, which versions the on-disk NogginDocument. Both are exported as constants.