Initialize the auth client by loading the session from storage or detecting it from the URL after an OAuth, magic-link, or password-recovery redirect.
Most callers do not need to invoke this directly. The client calls it automatically during construction, and to react to sign-in events (including post-redirect events) you should subscribe to onAuthStateChange rather than awaiting initialize().
You only need to call it manually when you have opted out of the automatic call by passing skipAutoInitialize: true — for example, in an SSR context where you need to control initialization timing. In that case, awaiting initialize() returns the resolved session result (or any error encountered while detecting it from the URL).