Package-level declarations

Archetype-D-simplest: a record-only gateway for cash collected outside the app entirely (courier COD, in-person handoff). Unlike mobile-money, there is no provider to even ping — pay() does nothing but record intent and return Pending; the order is only ever resolved when a human (merchant/cashier) confirms the cash was received, via the backend's /mock/cash/{orderId}/settle reconciliation route. No SDK, no WebView, no network call from this gateway at all.