/**
 * Internal HTTP helpers for the public DEX fetchers.
 *
 * SSOT rule #2 boilerplate consolidation: every public fetcher needed the
 * same 5-line "throw on non-2xx with body excerpt" guard. Centralized here
 * so each call site is one assertOk(...) line.
 */
/**
 * Throw if the Response is not OK, with HTTP status + (truncated) body
 * excerpt for diagnostics.
 *
 * Use BEFORE `res.json()` so a 5xx JSON error body cannot fulfill as if it
 * were valid data.
 */
export declare function assertOk(res: Response, label: string): Promise<void>;