/**
 * A registry of element-scoped cancellation callbacks.
 *
 * The runtime registers a cancel callback per Island element that has pending
 * Gate work (e.g. a `client:visible` IntersectionObserver subscription). When
 * the element is removed from the DOM, or its containing Subtree is excluded,
 * those callbacks fire so the pending work doesn't leak.
 */
export interface CancellableWatchers {
    /**
     * Register a cancel callback for an element. Returns a dispose function that
     * removes just this callback (other callbacks for the same element stay).
     */
    watch(el: Element, cancel: () => void): () => void;
    /** Fire and forget every callback whose element is no longer connected. */
    cancelDetached(): void;
    /** Fire and forget every callback whose element is inside `root`. */
    cancelInRoot(root: Element): void;
}
export declare function createCancellableWatchers(): CancellableWatchers;