VSN-2942/feat(exploitation): readable « N° » code USA/CHA/CLI with sort, filter and search

Replace the UUID in the « N° » column with a contiguous sequential code (sequentialNumber + sequentialCode) on the usager / chauffeur / client DTOs, allocated on creation and on import. Add sort and filter by sequence number (USA1 / usa1 / 1) and expose sequentialNumber in the Emploi du temps projection. Fix passenger search returning a null sequentialCode because the grid maps through PassengerMapper.toDtoLean instead of toDTO.