Clears both activeCompanyId and preferences (call on logout).
Current active-company selection, or null if none set.
One stored preference by key.
All stored preferences.
Sets (or clears, with null) the active-company selection.
Sets one preference by key.
Subscribe to any change made through this instance. Returns an unsubscribe function.
Client-persisted UX state: the active company switcher selection + preferences. NOT an authorization source — never trusted server-side, see this file's own header comment.