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/oauth.ts

@@ -0,0 +1,10 @@
+/** Type-only compatibility entry point for coding-agent extension OAuth declarations. */
+export type {
+	OAuthAuthInfo,
+	OAuthCredentials,
+	OAuthDeviceCodeInfo,
+	OAuthLoginCallbacks,
+	OAuthPrompt,
+	OAuthSelectOption,
+	OAuthSelectPrompt,
+} from "./compat/extension-oauth-types.ts";