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/coding-agent/examples/rpc-client.ts

@@ -0,0 +1,35 @@
+/**
+ * Run one prompt through a Pi RPC child process.
+ *
+ * Build the coding-agent package first, then run:
+ * node examples/rpc-client.ts "Explain this repository"
+ */
+
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { RpcClient } from "@earendil-works/pi-coding-agent";
+
+const exampleDirectory = dirname(fileURLToPath(import.meta.url));
+const prompt = process.argv.slice(2).join(" ") || "Explain this repository in one paragraph.";
+
+const client = new RpcClient({
+	cliPath: join(exampleDirectory, "../dist/cli.js"),
+	args: ["--no-session"],
+});
+
+const unsubscribe = client.onEvent((event) => {
+	if (event.type === "message_update" && event.assistantMessageEvent.type === "text_delta") {
+		process.stdout.write(event.assistantMessageEvent.delta);
+	} else if (event.type === "tool_execution_start") {
+		process.stderr.write(`\n[tool: ${event.toolName}]\n`);
+	}
+});
+
+try {
+	await client.start();
+	await client.promptAndWait(prompt);
+	process.stdout.write("\n");
+} finally {
+	unsubscribe();
+	await client.stop();
+}