chore(vendor): import pi 0.85.1

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: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/chord/test/json.test.ts

@@ -0,0 +1,14 @@
+import { describe, expect, test } from "vitest";
+import { isJsonValue } from "../src/index.ts";
+
+describe("isJsonValue", () => {
+	test("checks strict JSON without normalizing it", () => {
+		expect(isJsonValue({ nested: [1, true, null] })).toBe(true);
+		expect(isJsonValue({ omitted: undefined })).toBe(false);
+		expect(isJsonValue(new Uint8Array([1]))).toBe(false);
+		expect(isJsonValue(Number.POSITIVE_INFINITY)).toBe(false);
+		const cyclic: { self?: unknown } = {};
+		cyclic.self = cyclic;
+		expect(isJsonValue(cyclic)).toBe(false);
+	});
+});