fix(cli): address code-review findings on auth PR

packages/cli/src/auth/index.ts

@@ -0,0 +1,17 @@
+/**
+ * Public surface of the auth library — only the symbols the auth
+ * commands consume today. Internal types stay in their source files.
+ */
+
+export { isAuthError } from "./errors.js";
+
+export { clearOAuth, deleteStore, isHeaderSafe, readStore, writeStore } from "./store.js";
+export type { Credentials } from "./store.js";
+
+export { configDir, credentialPath } from "./paths.js";
+
+export { tryResolveCredential } from "./resolver.js";
+export type { ResolvedCredential } from "./resolver.js";
+
+export { AuthClient } from "./client.js";
+export type { UserInfo } from "./client.js";