fix(assets): 手动送审如实回报,送不出去返回 503 而非空态

submit_asset_for_review 改为返回 bool(是否真进入审核);submit-review 端点据此:
当审核服务未启用/未配 SDK/火山未回 Id/调用异常导致没真正送出去,且素材非终态时,
返回 503「审核服务暂不可用」而不是空 review_status —— 否则前端会把「没送出去」
误显示成「审核中」,刷新就打回灰盾(待审核)。新增 503/200 两条回归测试。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/backend/apps/assets/views.py

@@ -125,8 +125,15 @@ class AssetViewSet(TeamScopedViewSetMixin, ModelViewSet):
         asset = self.get_object()  # team-scoped + is_deleted 过滤
         if asset.category not in Asset.REVIEW_CATEGORIES:
             return Response({"detail": "该素材无需审核"}, status=status.HTTP_400_BAD_REQUEST)
-        submit_asset_for_review(asset)
+        started = submit_asset_for_review(asset)
         asset.refresh_from_db()
+        # 没真正送出去(审核服务未启用/未配置 SDK/火山未回 Id/调用异常),且素材也不是已终态:
+        # 如实回报 503,别返回空 review_status —— 否则前端会把「没送出去」误显示成「审核中」,刷新就打回原形。
+        if not started and asset.review_status not in ("processing", "active", "failed"):
+            return Response(
+                {"detail": "审核服务暂不可用,请稍后重试", "review_status": asset.review_status or ""},
+                status=status.HTTP_503_SERVICE_UNAVAILABLE,
+            )
         return Response({"review_status": asset.review_status, "review_error": asset.review_error or ""})
 
     @action(detail=False, methods=["get"], url_path="video-packs")