Declare a bank transfer against an outstanding ledger entry

Executes the "Pay now" flow: the tenant DECLARES that it has wired the money for an outstanding ledger entry to the published payee account (see GET .../billing/payment-instructions). The entry moves to pending-manual-approval and, when receiptFileName is supplied, gains a placeholder awaiting-review SWIFT/EFT receipt. A charge (an invoice charge or a commitment upfront — a debt) keeps its type; a payment row becomes wire-transfer-pending. A declared debt cannot be cancelled by the tenant (…/actions/cancel answers 409). This action settles nothing. No invoice is flipped PAID, no wallet grant is credited, no commitment is activated and no ledger entry is marked completed. The platform stores no cards and runs no payment processor, so there is no instant settlement to offer: a platform Finance operator verifies the transfer arrived against the bank feed (SLA: 1 business day) and settles it exactly once through the operator confirm action — or resolves it with the operator reject action. Settlement is the operator's, never the payer's. Validation: the addressed transaction must exist in the scope (else NOT_FOUND); an already-completed entry is CONFLICT; method must be wire — method=card is REFUSED with CONFLICT (it is retired PSP-era surface that used to settle self-service); a settling credit-applied or refund movement is not payable (CONFLICT) — the customer never wires those; caller needs contributor/admin/owner or billing role, otherwise FORBIDDEN. Guards are evaluated before any mutation, so a refusal leaves the ledger entry and its linked invoice unchanged. Async & state: Asynchronous — 202 returning the transaction in pending-manual-approval (type unchanged for a charge, wire-transfer-pending otherwise); terminal states completed (operator-confirmed against the bank feed) or failed (operator-rejected / tenant-cancelled), emitted as resource.updated SSE frames with kind billing.transaction patching status and the receipt verification field. Errors: 401 unauthenticated; 403 insufficient role; 404 unknown scope/transaction; 409 CONFLICT entry already settled, entry type not payable, or method=card; 422 invalid method; 429 repeated payment attempts rate-limited; 500 ledger failure. Idempotency/Concurrency: This operation does not use Idempotency-Key; it may be omitted and a sent one is ignored. The entry is locked FOR UPDATE so concurrent declarations serialize; re-declaring an entry already in pending-manual-approval replaces its placeholder receipt rather than posting a second entry.