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);

third_party/pi/packages/codemode/test/fixtures/worker-process-exit.ts

@@ -0,0 +1,51 @@
+import { CodemodeSandbox } from "../../src/runtime/host.ts";
+
+const how = process.argv[2];
+if (how !== "abort" && how !== "timeout" && how !== "close") throw new Error(`Unknown stop mode: ${how}`);
+const started = performance.now();
+process.on("exit", () => {
+	console.log(JSON.stringify({ type: "exit", elapsedMs: performance.now() - started }));
+});
+const controller = new AbortController();
+let timer: ReturnType<typeof setTimeout> | undefined;
+let workerExited = false;
+const sandbox = new CodemodeSandbox({
+	memoryLimitBytes: 256 * 1024 * 1024,
+	onWorkerStarted: (exited) => {
+		void exited.then(() => {
+			workerExited = true;
+		});
+	},
+	tools: [
+		{
+			name: "ready",
+			execute: () => {
+				if (how !== "timeout") {
+					timer = setTimeout(() => {
+						if (how === "abort") controller.abort();
+						else void sandbox.close();
+					}, 100);
+				}
+			},
+		},
+	],
+});
+try {
+	const result = await sandbox.execute(
+		"await tools.ready(); return 'a'.repeat(300000).indexOf('a'.repeat(10000) + 'b')",
+		{ signal: controller.signal, timeoutMs: how === "timeout" ? 300 : Number.POSITIVE_INFINITY },
+	);
+	if (result.ok) throw new Error("The script completed instead of being cancelled");
+	await sandbox.close();
+	console.log(
+		JSON.stringify({
+			type: "result",
+			kind: result.error.kind,
+			elapsedMs: performance.now() - started,
+			workerExited,
+		}),
+	);
+} finally {
+	clearTimeout(timer);
+	await sandbox.close();
+}