Adds bookable assets (rooms, campsites, vehicles, equipment) to the connected Nexwin account, up to 100 in one call, and tells the live receptionist about them. Use it to set up a whole list the user has pasted or uploaded. All of them are added or none: if any row is invalid, or a name is already in use, nothing is saved and the error says which row. Identical units go in one asset with a quantity (e.g. "Standard Room", quantity 12) rather than twelve assets. bookingType: nightly (check in one day, out a later day), day (a block within one day), date_range (whole days), or not_applicable. Executes immediately. Call list_assets first to avoid clashing names.