export declare const fmtUsd: (n: number) => string;
export declare const fmtInt: (n: number) => string;
/**
 * Estimate how many tokens a USD budget buys at a given per-token price.
 * Returns null when the price is missing or non-positive.
 */
export declare const estimateTokensFromBudget: (budget: number, pricePerToken?: number) => number | null;