Keep process alive reliably with unref interval in waitForever

src/index.ts

@@ -384,8 +384,11 @@ async function startWebhook(
 }
 
 function waitForever() {
+  // Keep event loop alive via an unref'ed interval plus a pending promise.
+  const interval = setInterval(() => {}, 1_000_000);
+  interval.unref();
   return new Promise<void>(() => {
-    /* never resolve to keep process alive */
+    /* never resolve */
   });
 }