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/ai/src/api/pi-messages.lazy.ts

@@ -0,0 +1,4 @@
+import type { ProviderStreams } from "../types.ts";
+import { lazyApi } from "./lazy.ts";
+
+export const piMessagesApi = (): ProviderStreams => lazyApi(() => import("./pi-messages.ts"));