/**
 * useTr — translation hook with fallback semantics.
 *
 * Wraps `useI18n().t()` so that when a key has no translation (i.e. the
 * provider returns the key itself), the caller's English fallback is used
 * instead. This keeps consumer call sites consistent and avoids leaking
 * untranslated keys into the UI.
 *
 * Supports optional interpolation params using `{{key}}` placeholders.
 *
 * @example
 *   const tr = useTr();
 *   return <h1>{tr('support.ticketList.title', 'Support Tickets')}</h1>;
 *   return <p>{tr('support.ticketList.count', '{{count}} tickets', { count: 5 })}</p>;
 */
export declare function useTr(): (key: string, fallback: string, params?: Record<string, string | number>) => string;