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/scripts/coding-agent-smoke.mjs

@@ -0,0 +1,51 @@
+import { execFileSync } from "node:child_process";
+import { mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+export const codingAgentName = "@earendil-works/pi-coding-agent";
+
+export function smokeTestCodingAgent(directory, runtime = process.execPath) {
+	const packageDir = join(directory, "node_modules", codingAgentName);
+	const manifest = JSON.parse(readFileSync(join(packageDir, "package.json"), "utf8"));
+	const home = mkdtempSync(join(tmpdir(), "pi-coding-agent-smoke-home-"));
+	const entry = join(directory, "coding-agent-smoke.mjs");
+	const env = {
+		PATH: process.env.PATH,
+		HOME: home,
+		USERPROFILE: home,
+		APPDATA: home,
+		LOCALAPPDATA: home,
+		XDG_CONFIG_HOME: home,
+		XDG_CACHE_HOME: home,
+		PI_CODING_AGENT_DIR: join(home, ".pi", "agent"),
+		PI_OFFLINE: "1",
+		PI_TELEMETRY: "0",
+	};
+	for (const name of ["SystemRoot", "SYSTEMROOT", "WINDIR", "COMSPEC", "PATHEXT"]) {
+		if (process.env[name]) env[name] = process.env[name];
+	}
+	try {
+		writeFileSync(entry, `import assert from "node:assert/strict";
+import { createAgentSession, SessionManager, ModelRuntime } from "${codingAgentName}";
+assert.equal(typeof createAgentSession, "function");
+assert.equal(typeof SessionManager.inMemory, "function");
+assert.equal(typeof ModelRuntime.create, "function");
+`);
+		execFileSync(runtime, [entry], { cwd: directory, env, stdio: ["inherit", "pipe", "pipe"], timeout: 30_000 });
+		for (const cli of new Set([manifest.bin.pi, "dist/cli.js"])) {
+			const output = execFileSync(runtime, [join(packageDir, cli), "--version"], {
+				cwd: directory,
+				encoding: "utf8",
+				env,
+				stdio: ["inherit", "pipe", "pipe"],
+				timeout: 30_000,
+			});
+			if (output.trim() !== manifest.version) throw new Error(`Unexpected version from ${cli}: ${output}`);
+		}
+	} finally {
+		rmSync(entry, { force: true });
+		rmSync(home, { recursive: true, force: true });
+	}
+	console.log(`Coding-agent policy smoke tests passed (${runtime}).`);
+}