SignReply:
| { ok: true; sigB64: string }
| { ok: true; valid: boolean }
| { ok: true; pem: string }
| { ok: true; privatePem: string; publicPem: string }
| { b64: string; ok: true; tagB64?: string }
| { details: Record<string, unknown>; ok: true }
| { ok: true; parsed: Record<string, unknown> }
| { hex: string; ok: true }
| { error: string; ok: false }
what it gets back