type ActivityListener = () => void;
/**
 * Start listening for real user-input events. Safe to call multiple times;
 * listeners are only attached once.
 */
export declare function initActivityTracking(): void;
/**
 * Register a callback that fires (throttled) whenever genuine user activity
 * occurs. Returns an unsubscribe function.
 */
export declare function onUserActivity(fn: ActivityListener): () => void;
/** Milliseconds since the last detected user activity. */
export declare function timeSinceLastActivity(): number;
/** Timestamp (ms) of the last detected user activity. */
export declare function getLastActivity(): number;
export {};