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/coding-agent/src/utils/sleep.ts

@@ -0,0 +1,18 @@
+/**
+ * Sleep helper that respects abort signal.
+ */
+export function sleep(ms: number, signal?: AbortSignal): Promise<void> {
+	return new Promise((resolve, reject) => {
+		if (signal?.aborted) {
+			reject(new Error("Aborted"));
+			return;
+		}
+
+		const timeout = setTimeout(resolve, ms);
+
+		signal?.addEventListener("abort", () => {
+			clearTimeout(timeout);
+			reject(new Error("Aborted"));
+		});
+	});
+}