/**
 * Identity key for presence rosters.
 *
 * Lives here rather than beside selectHeaderCollaborators so P1PuckProvider can
 * import it without depending on the editor plugin.
 */
import type { ActorPresence } from '@pantheon-systems/css-client';
/**
 * Identity key for the provider memo that publishes presence on the context.
 *
 * The context exposes `presence` through a getter so a focus-region broadcast
 * doesn't recreate it, which means consumers only observe new presence when that
 * memo's deps change. Actor *count* is not enough to detect a change:
 *
 *  - a leave and a join in the same WS frame keeps the count identical, so the
 *    header would keep rendering whoever left;
 *  - `userNameResolver` filling in display names asynchronously rewrites `name`
 *    and `avatar` without touching the count.
 *
 * Used for both rosters, so it covers the union of what each one renders:
 *
 *  - human avatars (PresenceStack) use actorId, name, avatar and state — state
 *    drives the live dot, and a transition changes neither count nor ids;
 *  - the agent's banner uses name and intent, and its block marker (mapped in
 *    focusRegionMap) uses actorId, state, requestedByName and agentKind (which
 *    picks the icon);
 *  - a Stop carries the agent's turnId, which decides whether a panel holding a
 *    turn of its own ends it, so a stale one would leave that turn running.
 *
 */
export declare function presenceIdentityKey(actors: ActorPresence[] | undefined | null): string;