[mjanthony819]

stdnum.no.orgnr accepts any 9-digit number with a valid modulus 11 check digit, so numbers like 100 000 008 validate successfully. Norwegian organisation numbers are only assigned from number series starting with 8 or 9.

Official sources:

• Brønnøysund Register Centre: https://www.brreg.no/om-oss/registrene-vare/om-enhetsregisteret/organisasjonsnummeret/
• Altinn dataset documentation: "Organisasjonsnummeret består av ni siffer og starter på tallet 8 eller 9" - https://docs.data.altinn.no/tjenester/ebevis/datasettdefinisjoner/

Reject numbers whose first digit is not 8 or 9 with InvalidComponent. The modulus 11 algorithm is unchanged. stdnum.no.mva delegates to this validator, so Norwegian VAT numbers inherit the stricter check.

Eight new regression cases pair a valid check digit with an invalid leading digit (0-7); all are accepted before the change and rejected after. Two constructed numbers starting with 8 and 9 confirm valid numbers remain accepted, alongside ten real numbers found online.

Validation on Python 3.10:

• All 414 configured tests and doctests pass (9 skipped), with the required 100% coverage maintained.
• Repository-wide flake8 passes.
• mypy reports no new errors.
• scripts/check_headers.py passes.

Fixes #275.

AI assistance covered research, implementation, tests and this description.