Validate a 9-char document number + 1-char check digit (10 chars total).
Returns true iff the input is exactly 10 chars, the body matches the
MRZ alphabet ([0-9A-Z<]{9}), the check digit is a single decimal,
and mrzCheckDigit(input.slice(0, 9)) === Number(input[9]).
Public algorithm primitives. Tree-shakable subpath:
nationid/algorithms.Each function is a pure mathematical primitive with cited spec.