Bug fix/fuel card extraction
- Aligns fuel card retrieval logic between /api/user/driver/details/{id} and /api/user/driver/search
- Replaces getFuelCardNameById() with getFuelCardNumberById() in DriverDetailMapper to get actual card numbers from Fleet service
- Populates fuelCardNames with actual card numbers instead of null values
- Automatically fills vehicle.fuelCardNumber with the first card found if available
- Uses FunctionalException with error codes instead of generic exceptions for better tracing