/**
 * Real-time collaboration. Presence (who else is here + where their cursor
 * is) and live edits (a change in one client lands in every other), over a
 * pluggable transport. The transport is the only thing tied to infrastructure
 * - swap `broadcastChannelTransport` (same-browser tabs, zero backend) for a
 * WebSocket / WebRTC / CRDT adapter and the controller is unchanged.
 *
 * This is also the natural "multiple agents on one grid" substrate: an AI
 * agent is just another peer posting `edit` messages.
 */
export type CollabUser = {
    id: string;
    name: string;
    /** A CSS color for this user's cursor / avatar. */
    color: string;
};
export type CollabCell = {
    rowId: string;
    columnId: string;
};
export type CollabPresence = CollabUser & {
    cell: CollabCell | null;
    /** Last time we heard from this peer (ms). Used to prune the gone. */
    ts: number;
};
export type CollabMessage = {
    kind: 'hello';
    user: CollabUser;
} | {
    kind: 'presence';
    user: CollabUser;
    cell: CollabCell | null;
} | {
    kind: 'edit';
    user: CollabUser;
    rowId: string;
    columnId: string;
    value: unknown;
} | {
    kind: 'bye';
    userId: string;
};
export type CollabTransport = {
    post(msg: CollabMessage): void;
    subscribe(handler: (msg: CollabMessage) => void): () => void;
    /** Release any underlying resource (e.g. a BroadcastChannel). Optional. */
    dispose?(): void;
};
export type Collaboration = {
    /** Broadcast where this user's cursor is (or null when it leaves). */
    setCell(cell: CollabCell | null): void;
    /** Broadcast a cell edit to every peer. */
    sendEdit(rowId: string, columnId: string, value: unknown): void;
    /** The peers currently present (excludes self). */
    peers(): CollabPresence[];
    dispose(): void;
};
export type CollaborationOptions = {
    user: CollabUser;
    transport: CollabTransport;
    /** Fired (with self excluded) whenever the peer set or a cursor changes. */
    onPeersChange?: (peers: CollabPresence[]) => void;
    /** Fired when another user edits a cell - apply it to your data. */
    onRemoteEdit?: (edit: {
        rowId: string;
        columnId: string;
        value: unknown;
        user: CollabUser;
    }) => void;
    /** Drop peers we haven't heard from in this many ms. Default 15000. */
    peerTimeoutMs?: number;
};
/** BroadcastChannel transport - live across tabs of the same browser, no
 *  backend. No-ops where BroadcastChannel is unavailable (SSR / old env). */
export declare function broadcastChannelTransport(name: string): CollabTransport;
export declare function createCollaboration(options: CollaborationOptions): Collaboration;