fix(ecommerce): video 400 error — use OSS URLs instead of data URLs for video generation

The renderScene function was passing local data URLs (data:image/png;base64,...)
as imageUrl and referenceUrls to createVideoTask, which the /api/ai/video endpoint
rejects with 400 Bad Request. The planning phase already uploads images to OSS
but the resulting URLs were not returned to the component.

- Add imageUrls field to EcommerceVideoPlanResult
- Return OSS imageUrls from runVideoPlan alongside existing plan data
- Use planResult.imageUrls[0] in handleRender instead of productImageDataUrls[0]
- Use planResult?.imageUrls[0] for sourceImage display fallback

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/styles/components/primitives.css

@@ -65,18 +65,7 @@
   min-height: 0;
 }
 
-.page-motion--exit {
-  animation: page-out 180ms ease both;
-  pointer-events: none;
-}
-
-.page-motion--exit .page-motion {
-  animation: none;
-}
-
-@keyframes page-out {
-  to { opacity: 0; transform: translateY(-6px); }
-}
+/* page-motion--exit moved to page-transition.css */
 
 .page-loading-center {
   display: flex;