/**
 * Compile-time-only type-accuracy check for SDK 0.67.0's bonus-spend preview
 * surface. Same pattern as types.reorder.typecheck.ts: no runtime assertions,
 * never imported by index.ts — `bun:test` won't pick it up (the name doesn't
 * match `*.test.ts`) and `bun build` won't bundle it, but `tsc --noEmit` /
 * `tsc --emitDeclarationOnly` fails loudly if the types drift from the wire.
 *
 * What is pinned here, and WHY each is worth a compile-time fixture:
 *
 *  - The seven MONEY/echo CheckoutPreview fields are REQUIRED. There is no
 *    deployment that answers this route with a subset of THOSE — it either
 *    exists and sends all seven or 404s — so an optional money field would push
 *    a phantom `undefined` branch into every storefront that renders the
 *    breakdown. The eighth field, `bonusExpiringSoon`, is optional on purpose
 *    and is EXEMPTED BY NAME below rather than by relaxing the pin: it postdates
 *    the route, so an API deployed in between answers 200 without the key. The
 *    exemption is spelled out so the next additive field has to be argued for
 *    too, instead of arriving under a blanket `Partial`.
 *
 *  - CheckoutPreview is NOT InsufficientBalanceDetails with different names.
 *    The two describe the same arithmetic at different moments and share a field
 *    NAME (`shortfallAmount`) with a DIFFERENT floor: the 402's is never below 1
 *    (a refusal always needs a real top-up), the preview's is 0 on an affordable
 *    cart. A maintainer "harmonizing" the two shapes would silently offer buyers
 *    a 1 ₽ top-up they don't need — or hide a top-up they do.
 *
 *  - `useBonus` is NOT a CheckoutRequest body field in this SDK. It travels in
 *    the create OPTIONS. Two spellings for one decision would need a precedence
 *    rule, and picking the wrong one spends bonuses the buyer withheld.
 *
 *  - `checkout.create`'s second parameter accepts BOTH a bare key string and the
 *    options bag. Shipped storefronts call it positionally, so the union may
 *    only ever be EXTENDED. This has to be pinned HERE, in typechecked scope:
 *    tsconfig excludes `*.test.ts`, so the wire tests' positional calls are
 *    never compiled, and bun's runner never typechecks. Narrowing the parameter
 *    to `CheckoutCreateOptions` alone would therefore pass both `tsc` and the
 *    whole suite while breaking every consumer's build — a silent break of the
 *    one interface those storefronts depend on.
 */
export {};