chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/codemode/test/fixtures/raw-worker.ts

@@ -0,0 +1,8 @@
+/**
+ * Stands in for the real worker in host tests: posts the JSON message (or array of messages) passed
+ * as the script source, so tests can send the host payloads the real prelude never produces.
+ */
+import { parentPort, workerData } from "node:worker_threads";
+
+const messages: unknown = JSON.parse((workerData as { code: string }).code);
+for (const message of Array.isArray(messages) ? messages : [messages]) parentPort?.postMessage(message);