Method subscribeToDelete

ui/src/protocol/message-processor.ts:519–531

* Subscribe to surface deletion events * @param surfaceId - The surface ID to watch for deletion * @param listener - Callback when surface is deleted * @returns Unsubscribe function

(surfaceId: string, listener: (surfaceId: string) => void)

   * @returns Unsubscribe function
   */
  subscribeToDelete(surfaceId: string, listener: (surfaceId: string) => void): () => void {
    let listeners = this.deleteListeners.get(surfaceId);
    if (!listeners) {
      listeners = new Set();
      this.deleteListeners.set(surfaceId, listeners);
    }
    listeners.add(listener);

    // Return unsubscribe function
    return () => {
      listeners?.delete(listener);
    };
  }

  /**
   * Notify delete listeners of surface deletion