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/test/suite/regressions/9540-extension-loader-lazy.test.ts

@@ -0,0 +1,58 @@
+import { describe, expect, it, vi } from "vitest";
+
+const state = vi.hoisted(() => ({
+	jitiModuleLoads: 0,
+	jitiStaticModuleLoads: 0,
+	virtualModulesLoads: 0,
+	createJiti: vi.fn((_id: unknown, _options: unknown) => ({
+		import: vi.fn(async () => () => {}),
+	})),
+}));
+
+vi.mock("jiti", () => {
+	state.jitiModuleLoads++;
+	return { createJiti: state.createJiti };
+});
+
+vi.mock("jiti/static", () => {
+	state.jitiStaticModuleLoads++;
+	return { createJiti: state.createJiti };
+});
+
+vi.mock("../../../src/core/extensions/virtual-modules.ts", () => {
+	state.virtualModulesLoads++;
+	return { VIRTUAL_MODULES: {} };
+});
+
+import { loadExtensions } from "../../../src/core/extensions/loader.ts";
+
+interface JitiOptionsProbe {
+	alias?: unknown;
+	tryNative?: boolean;
+	tsconfigPaths?: boolean;
+	virtualModules?: Record<string, unknown>;
+}
+
+describe("extension loader lazy imports", () => {
+	// Regression test for #9540.
+	it("defers ordinary jiti and its virtual modules until importing an extension", async () => {
+		expect(state.jitiModuleLoads).toBe(0);
+		expect(state.jitiStaticModuleLoads).toBe(0);
+		expect(state.virtualModulesLoads).toBe(0);
+
+		const result = await loadExtensions(["/extension.ts"], "/");
+
+		expect(result.errors).toEqual([]);
+		expect(result.extensions).toHaveLength(1);
+		expect(state.jitiModuleLoads).toBe(1);
+		expect(state.jitiStaticModuleLoads).toBe(0);
+		expect(state.virtualModulesLoads).toBe(1);
+		expect(state.createJiti).toHaveBeenCalledOnce();
+
+		const options = state.createJiti.mock.calls[0][1] as JitiOptionsProbe;
+		expect(options.tryNative).toBeUndefined();
+		expect(options.tsconfigPaths).toBe(true);
+		expect(options.alias).toBeUndefined();
+		expect(options.virtualModules).toBeDefined();
+	});
+});