OptionalPrepareAdjusts the loaded configuration BEFORE it is published to any subscriber.
The shell uses this to make a deep link win on a full page load: the URL's query params are written into the matching restored tab before the tab container mounts that tab's component. Applying them afterwards (when the resolver's queued tab request replays) is too late — the component has already initialised from the saved params, and an async init that writes its selection back can clobber the URL's params entirely.
Return the same object for "no change"; a different object is published and persisted.
Options for WorkspaceStateManager.Initialize.