Mark 0-euro transaction as handled

Marks a bank transaction with amount 0 as dismissed without creating a booking. 0-euro transactions (e.g. fee refunds, test bookings, balance notifications) have no accounting effect and therefore cannot be reconciled normally — dismiss is the intended way to flag them as handled. An accidental dismiss can be undone via the existing unmatch endpoint (`POST /v1/bank-transactions/:id/unmatch`).

-cmd">curl --request -method">POST -punct">\
  --url 'https://api.ledgerlou.de/v1/bank-transactions/:id/dismiss' -punct">\
  --header 'Authorization: Bearer ll_your_key'

{
  "ok": true
}