Expose Dataspace value in Entity's data field

packages/core/src/runtime/dataspace.ts

@@ -20,6 +20,7 @@ export class Dataspace implements Partial<Entity> {
     readonly index = new Index();
     readonly handleMap = new IdentityMap<Handle, Assertion>();
     readonly observerMap = new IdentityMap<Ref, IndexObserver<Turn>>();
+    readonly data = this;
 
     constructor(options?: DataspaceOptions) {
         this.options = options ?? {};