/** Best-effort human text for anything thrown — SDK rejections are rarely Errors. */
export function errorMessage(err: unknown): string {
  if (err instanceof Error) return err.message;
  if (err && typeof err === "object") {
    const obj = err as Record<string, unknown>;
    if (typeof obj.message === "string") return obj.message;
    if (typeof obj.error === "string") return obj.error;
    try {
      return JSON.stringify(err);
    } catch {}
  }
  return String(err);
}