Need an API for logout

Rather than assuming that the app knows to call window.localStorage.clear() or whatever

The issue does not name a file, entry point, or test; begin by locating the SDK's session and logout-related APIs and reviewing how local authentication state is managed. Define the logout API's expected behavior, including whether it clears local state, then add coverage for that behavior and verify the existing test suite.

Written by the indexing model from the issue text.