Function mapError

packages/computer/src/artifacts/cli.ts:715–721

* Map a thrown error to the standard `artifacts : * ` framing at exit 1. ArtifactError subclasses carry a * clean message; anything else stringifies its cause.

(subcommand: string, cause: unknown)

 * clean message; anything else stringifies its cause.
 */
function mapError(subcommand: string, cause: unknown): ArtifactsCLIResult {
  if (cause instanceof ArtifactError) {
    return { stdout: "", stderr: `artifacts ${subcommand}: ${cause.message}\n`, exitCode: 1 };
  }
  const message = cause instanceof Error ? cause.message : String(cause);
  return { stdout: "", stderr: `artifacts ${subcommand}: ${message}\n`, exitCode: 1 };
}

// ---------------------------------------------------------------
// flag parser