fix: close final viewer integration gaps (#5)

apps/viewer-3d/src/viewer/ThreeDViewer.ts

@@ -29,6 +29,7 @@ export class ThreeDViewer {
   private readonly onError;
   private readonly fps = createFpsMeter();
   private readonly adaptive;
+  private disposed = false;
   private raf = 0;
   private current: THREE.Object3D | null = null;
   private outline: THREE.Group | null = null;
@@ -323,6 +324,7 @@ export class ThreeDViewer {
   };
 
   private animate = (now: number = performance.now()): void => {
+    if (this.disposed) return;
     this.raf = requestAnimationFrame(this.animate);
     this.fps.sample(now);
     this.adaptive.update(this.fps.fps());
@@ -331,14 +333,20 @@ export class ThreeDViewer {
   };
 
   dispose(): void {
+    if (this.disposed) return;
+    this.disposed = true;
     cancelAnimationFrame(this.raf);
+    this.raf = 0;
     window.removeEventListener('resize', this.onResize);
     this.controls.dispose();
     this.clearOutline();
     if (this.current) this.disposeObject(this.current);
+    this.current = null;
     this.fps.el.remove();
     this.renderer.dispose();
+    this.renderer.forceContextLoss();
     this.renderer.domElement.remove();
+    this.scene.clear();
   }
 
   /** Orbit the camera to azimuth (radians) around the model — used by tools/prerender.mjs. */