#FORMAT is a compulsory record in every SIE type and PC8 is its only
legal value. We only emitted it when the caller opted into cp437 byte
encoding, so the default UTF-8 download had no #FORMAT line and strict
importers (Visma Spiris) rejected the file with 'Etiketten #FORMAT
saknas i filen'. Cloud exporters (Fortnox, Bokio) ship UTF-8 bytes with
#FORMAT PC8 and importers detect the real encoding from the bytes, so
the tag is now unconditional.
Also formats #ORGNR as nnnnnn-nnnn per spec; company_settings stores
the org number without a hyphen.
Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>