/**
 * Fire-and-forget runner for webhook side-effects.
 *
 * Shopify expects a 200 response within ~5 seconds, otherwise it considers
 * the delivery failed and retries it. Heavy automation work (PDF render,
 * Shopify Files upload, SMTP send) routinely exceeded that budget, which
 * caused duplicate invoice emails before we added the dedupe table.
 *
 * Returning the response immediately and letting the work finish in the
 * background keeps Shopify happy. Combined with the dedupe table this is
 * defence-in-depth: dedupe ensures *correctness* even if a retry sneaks
 * through, while async processing makes retries unlikely in the first
 * place.
 *
 * Errors are caught and logged \u2014 they cannot reach a dispatcher because
 * the HTTP response is already gone.
 */
export function runWebhookInBackground(
  description: string,
  work: () => Promise<unknown>,
): void {
  // `void` so we don't accidentally `await` the floating promise; the
  // node event loop keeps the task alive until it settles.
  void work().catch((err) => {
    console.error(`background webhook task '${description}' failed:`, err);
  });
}