ui: add objectRegistry for memory management

pkgs/clan-app/ui/src/scene/ObjectRegistry.ts

@@ -0,0 +1,43 @@
+import * as THREE from "three";
+
+type ObjectEntry = {
+  object: THREE.Object3D;
+  type: string;
+  id: string;
+  dispose?: () => void;
+};
+
+export class ObjectRegistry {
+  #objects = new Map<string, ObjectEntry>();
+
+  add(entry: ObjectEntry) {
+    const key = `${entry.type}:${entry.id}`;
+    this.#objects.set(key, entry);
+  }
+
+  getById(type: string, id: string) {
+    return this.#objects.get(`${type}:${id}`);
+  }
+
+  getAllByType(type: string) {
+    return [...this.#objects.values()].filter((obj) => obj.type === type);
+  }
+
+  removeById(type: string, id: string, scene: THREE.Scene) {
+    const key = `${type}:${id}`;
+    const entry = this.#objects.get(key);
+    if (entry) {
+      scene.remove(entry.object);
+      entry.dispose?.();
+      this.#objects.delete(key);
+    }
+  }
+
+  disposeAll(scene: THREE.Scene) {
+    for (const entry of this.#objects.values()) {
+      scene.remove(entry.object);
+      entry.dispose?.();
+    }
+    this.#objects.clear();
+  }
+}