chore: import upstream snapshot with attribution

apps/webapp/test/fixtures/otlpErrorWorker.cjs

@@ -0,0 +1,7 @@
+// Real worker that always reports a failed task, to exercise the pool's error-outcome metric.
+const { parentPort } = require("node:worker_threads");
+
+parentPort.on("message", (message) => {
+  if (message && message.type === "pricing") return;
+  parentPort.postMessage({ id: message.id, ok: false, error: "boom" });
+});