Behaviors with Blueprint-style node graph, graph editor tab and BehaviorSystem

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/core/model/SceneObject.ts

@@ -13,9 +13,21 @@ export interface SceneObject {
   /** World position plus draw order (`z`). */
   position: Position;
   overrides: PropertyBag;
+  /**
+   * Another object of the same scene this one acts on (used by behaviors: "the owner").
+   * Empty string = none. Any object may carry one, only behaviors interpret it.
+   */
+  ownerId: string;
 }
 
 /** Creates a scene object; `z` defaults to 0 when the caller only has a 2D point. */
 export function createSceneObject(id: string, assetId: string, position: Vec2 | Position): SceneObject {
-  return { id, assetId, name: '', position: { x: position.x, y: position.y, z: 'z' in position ? position.z : 0 }, overrides: {} };
+  return {
+    id,
+    assetId,
+    name: '',
+    position: { x: position.x, y: position.y, z: 'z' in position ? position.z : 0 },
+    overrides: {},
+    ownerId: '',
+  };
 }