Soft-deletes the vehicle and, in the same transaction, removes it from every technician's vehicle list. It no longer appears in listVehicles or getVehicle and can no longer be auto-selected for a crew.
Jobs that referenced it keep the stored reference but no longer display an assigned vehicle, and upcoming jobs are NOT given a replacement automatically. Reach for this only when a vehicle leaves the fleet for good (sold, written off, off-lease). For a van that is merely in the workshop, set its `status` to maintenance with updateVehicle instead, so the record stays in the fleet and can be brought straight back.
