Handle AtlasFlux API errors and retries

{
  "type": "error",
  "error": {
    "message": "AtlasFlux request rate limit exceeded.",
    "type": "rate_limit_error",
    "code": "rate_limit_exceeded",
    "param": null,
    "request_id": "req_abc123",
    "guidance": "Wait for the retry interval, then send the request again. Use the Retry-After header when available.",
    "action_url": null,
    "retryable": true,
    "retry_after_seconds": 12
  }
}

async function callAtlasFlux(input, attempt = 0) {
  const res = await fetch("https://api.atlasflux.my/v1/responses", {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${process.env.ATLASFLUX_API_KEY}`,
    },
    body: JSON.stringify({
      model: "atlasflux/nenas-flash",
      input,
      max_output_tokens: 1024,
    }),
  });

  if (res.ok) return res.json();

  const body = await res.json();
  const error = body.error;
  const retryAfter = error.retry_after_seconds ?? Number(res.headers.get("retry-after") ?? 0);
  const canRetry = error.retryable && attempt < 3;

  if (canRetry) {
    const delayMs = retryAfter > 0 ? retryAfter * 1000 : 2 ** attempt * 500;
    await new Promise((resolve) => setTimeout(resolve, delayMs));
    return callAtlasFlux(input, attempt + 1);
  }

  throw new Error(`${error.message} Request ID: ${error.request_id}`);
}