/**
 * Minimal external store for the drag-selection highlight band.
 *
 * Why an external store instead of React state: the selection gesture must
 * not re-render the history cards. Selection coordinates already live in a
 * ref (see use-history-controller) precisely so a drag causes zero renders;
 * this store gives the one leaf that DOES need to update — the right-edge
 * rail — a subscription channel. The controller publishes on every selection
 * mutation, and only components that call useSyncExternalStore on the store
 * re-render. Cards never subscribe, so they never re-render mid-drag, and
 * because the band renders inside the rail's already-reserved columns the
 * layout (and the fixed-height overflow-hidden viewport) cannot change.
 *
 * Snapshots are immutable; `publish` suppresses value-identical updates so a
 * drag that holds the same row span doesn't spam listeners.
 */
/** Row span of an in-progress drag, in viewport rows (0-based, inclusive). */
export interface SelectionBand {
    readonly topRow: number;
    readonly bottomRow: number;
    /** Row under the live drag head — rendered denser so the user can see
     * where the gesture currently points. */
    readonly headRow: number;
}
export type SelectionBandSnapshot = SelectionBand | null;
export interface SelectionBandStore {
    subscribe(listener: () => void): () => void;
    getSnapshot(): SelectionBandSnapshot;
    publish(next: SelectionBandSnapshot): void;
}
/** Band covering the anchor..head row span of an in-progress drag. */
export declare function bandFromSelection(anchor: {
    row: number;
}, head: {
    row: number;
}): SelectionBand;
export declare function createSelectionBandStore(): SelectionBandStore;
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