validateVin static method
Validates a 17-character VIN payload checking structure and position 9 check digit.
Implementation
static bool validateVin(String vin) {
final clean = vin.trim().toUpperCase();
if (clean.length != 17 || !_vinRegex.hasMatch(clean)) return false;
final expectedCheckDigit = calculateCheckDigit(clean);
return clean[8] == expectedCheckDigit;
}