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/durable/test/examples/18-print.ts

@@ -0,0 +1,53 @@
+// Print mode: submit one prompt and print its answer, like `pi -p`. The host awaits its own Submission, not global
+// idle. Uses OpenAI when OPENAI_API_KEY is set, and a scripted faux model otherwise.
+// Run from packages/durable:
+//   node --conditions=source --experimental-strip-types test/examples/18-print.ts "What is in this directory?"
+import { BACKGROUND_CONTEXT } from "@earendil-works/chord/context";
+import type { AssistantMessage } from "@earendil-works/pi-ai";
+import { createModels } from "@earendil-works/pi-ai/models";
+import { fauxAssistantMessage, fauxProvider, fauxText, fauxToolCall } from "@earendil-works/pi-ai/providers/faux";
+import { openaiProvider } from "@earendil-works/pi-ai/providers/openai";
+import { NodeExecutionEnv } from "../../src/env/node.ts";
+import { AssistantEntry, createRegistry, defineExtension, Harness, MemoryStorage, section } from "../../src/index.ts";
+import { createBashTool, createReadTool } from "../../src/tools/index.ts";
+
+const context = BACKGROUND_CONTEXT;
+const prompt = process.argv[2] ?? "What is in this directory?";
+
+const models = createModels();
+let model = { provider: "openai", modelId: "gpt-6-sol" };
+if (process.env.OPENAI_API_KEY !== undefined) {
+	models.setProvider(openaiProvider());
+} else {
+	const faux = fauxProvider();
+	models.setProvider(faux.provider);
+	model = { provider: "faux", modelId: "faux-1" };
+	faux.setResponses([
+		fauxAssistantMessage([fauxToolCall("bash", { command: "ls" }, { id: "call-1" })], { stopReason: "toolUse" }),
+		fauxAssistantMessage([fauxText("This directory holds the durable package sources, tests, and docs.")]),
+	]);
+}
+
+const registry = createRegistry();
+registry.install(
+	defineExtension({
+		name: "coding",
+		tools: [createReadTool(), createBashTool()],
+		sections: [section("preamble", () => "You are a concise coding assistant.", { tag: false })],
+	}),
+);
+const env = new NodeExecutionEnv({ cwd: process.cwd() });
+const harness = await Harness.open(new MemoryStorage(), { models, registry, env: () => env }, context);
+const root = await harness.root(context, { agent: { model } });
+
+const submission = await root.submit({ type: "input", content: prompt }, context);
+const settled = await submission.wait(context);
+if (settled.status === "done" && settled.type === "input") {
+	const entry = await root.commit((tx) => tx.entry(AssistantEntry, settled.answer), context);
+	const answer = entry?.model?.[0] as AssistantMessage;
+	console.log(answer.content.flatMap((content) => (content.type === "text" ? [content.text] : [])).join(""));
+} else {
+	console.error(`unanswered: ${settled.status === "unanswered" ? settled.reason : settled.status}`);
+	process.exitCode = 1;
+}
+await harness.close(context);