be: tell fees, interest and ATM withdrawals apart in Transaction.Method #66

Transaction.method() knows a transfer (clearingSystemReference ending in PAYMENT_ORDER_DOMESTIC) and a card payment (ending in PAYMENT_CARD); anything else is OTHER, with the code still in raw(). Both were read live, pending and booked (#43).

Not seen on the account yet, so not mapped:

• a bank fee
• interest
• an ATM withdrawal (a card movement, but not a payment)
• a refund of a card payment, and a hold that lapses
• a standing order, a direct debit, a foreign (SEPA, SWIFT) transfer

For each: record it with make record-fixture once one appears, note its clearingSystemReference and bankTransactionCode in .docs/moneta-api.md, and add a Method constant only if a caller would filter by it. The portal documentation (#11) may list the values up front.