API errors

1. Parse the body defensively; it may not be JSON (for example a proxy failure).
2. If `code` exists, branch on `code`. It is stable.
3. Otherwise use `status` (or `statusCode` for framework errors).
4. Fall back to `message` for logging only, never for logic.
5. Treat 5xx messages as sanitized and non-actionable.

{
  "status": 200,
  "message": "Restore operation completed with errors",
  "data": {
    "status": 400,
    "message": "Cannot restore the current version"
  }
}

base 1s, multiplier 2, cap 30s, full jitter, max 5 attempts

type ApiError = {
  status: number;
  message: string;
  code?: string;
};

function normalize(payload: unknown, httpStatus: number): ApiError {
  const body = (payload ?? {}) as Record<string, unknown>;
  return {
    status: httpStatus,
    message: typeof body.message === "string" ? body.message : "Unknown error",
    code: typeof body.code === "string" ? body.code : undefined,
  };
}

function shouldRetry(error: ApiError): boolean {
  if (error.status === 429) return true;
  if (error.status >= 500) return true;
  return false;
}