Scope note
Asset, Currency, and Rail Admission
The kind is neutral; deployments are concrete
FiatOfferV1.Terms commits escrow_kind_id, fiat_currency, and rail_id per offer. The same kind can therefore describe different admitted fungible assets and ISO-4217 currencies without gaining an exchange-rate oracle or performing cross-currency matching.
The Architecture of Record's Polish profile stores PLN in integer grosze and specifies BLIK P2P, Express Elixir, and same-bank internal transfers. Another currency or rail class requires its own immutable template, evidence, parameters, and deployment admission; the schema alone is not support.
A rail is eligible only if it exposes a timely authenticated record, a controllable reference, and a completion status with reviewed settlement meaning. Standard Elixir and card payments are outside v1 because delayed batches and chargebacks do not fit the offer window and irreversible release.
Support is template-specific
Each bank exposes different authenticated endpoints, status words, recipient fields, login challenges, and TLS behavior. A bank flow is supported only through an immutable rail template whose exact request, response ranges, field grammar, and completion semantics passed production and legal review.
There is no best-effort parser or automatic proxy fallback. A bank flow that fails a gate is outside the deployment; a reviewed replacement is a new deployment rather than a silent patch.