feat: 新增 POST /assets/batch 批量获取素材详情接口

前端 usePreviewAssets.ts 调用 POST /assets/batch 时返回 405 Method Not Allowed，
原因是后端没有 /batch GET/POST 端点，请求命中了 GET /{asset_id}（batch 被当成 asset_id）。

新增：
- BatchGetRequest schema：接收 { ids: string[] }，最多 200 个 ID
- POST /assets/batch 端点：调用 asset_repository.find_by_ids() 批量查询
- 返回 List[AssetResponse]，包含 file_url、duration、width、height 等完整元数据

改动文件：
- apps/api/app/schemas/asset.py：新增 BatchGetRequest
- apps/api/app/api/routes/assets.py：新增 batch_get_assets 端点

apps/api/app/api/routes/assets.py

@@ -1,5 +1,5 @@
 import logging
-from typing import Any, Optional
+from typing import Any, List, Optional
 
 from app.api.routes._helpers import check_project_access, format_utc_datetime
 from app.auth import AuthenticatedUser, get_current_user
@@ -14,6 +14,7 @@ from app.schemas.asset import (
     AssetResponse,
     BatchClassifyRequest,
     BatchDeleteRequest,
+    BatchGetRequest,
     BatchMarkRequest,
     BatchOperationResponse,
     BatchTagRequest,
@@ -370,6 +371,18 @@ def update_asset_review_status(
     return _to_asset_response(updated)
 
 
+@router.post("/batch", response_model=List[AssetResponse])
+def batch_get_assets(
+    request: BatchGetRequest,
+    authenticated_user: AuthenticatedUser = Depends(get_current_user),
+    asset_repository: Any = Depends(get_asset_repository),
+) -> list[AssetResponse]:
+    """批量获取素材详情（根据 ID 列表）。"""
+    items = asset_repository.find_by_ids(request.ids)
+    storage_service = get_storage_service()
+    return [_to_asset_response(item, storage_service) for item in items]
+
+
 @router.post("/batch-delete", response_model=BatchOperationResponse)
 def batch_delete_assets(
     request: BatchDeleteRequest,

apps/api/app/schemas/asset.py

@@ -58,6 +58,12 @@ class AssetResponse(BaseModel):
 MAX_BATCH_SIZE = 200
 
 
+class BatchGetRequest(BaseModel):
+    """批量获取素材详情请求。"""
+
+    ids: list[str] = Field(..., min_length=1, max_length=MAX_BATCH_SIZE, description="素材 ID 列表")
+
+
 class BatchDeleteRequest(BaseModel):
     """批量删除请求（软删除）。"""
 

apps/web/src/pages/generate/hooks/usePreviewAssets.ts

@@ -64,8 +64,11 @@ export function usePreviewAssets(assetIds: string[], enabled: boolean): UsePrevi
   const [ready, setReady] = useState(false)
   const requestIdRef = useRef(0)
 
+  // 稳定化 assetIds：只有内容真正变化时才更新引用
+  const stableAssetIds = useStableArray(assetIds)
+
   const load = useCallback(async () => {
-    if (!assetIds.length || !enabled) {
+    if (!stableAssetIds.length || !enabled) {
       setAssets([])
       setReady(false)
       return
@@ -76,7 +79,7 @@ export function usePreviewAssets(assetIds: string[], enabled: boolean): UsePrevi
     setReady(false)
 
     try {
-      const result = await fetchAssetsByIds(assetIds)
+      const result = await fetchAssetsByIds(stableAssetIds)
       // 防止竞态：只保留最新请求的结果
       if (requestIdRef.current === thisRequestId) {
         setAssets(result)
@@ -92,7 +95,7 @@ export function usePreviewAssets(assetIds: string[], enabled: boolean): UsePrevi
         setLoading(false)
       }
     }
-  }, [assetIds, enabled])
+  }, [stableAssetIds, enabled])
 
   useEffect(() => {
     load()
@@ -101,4 +104,22 @@ export function usePreviewAssets(assetIds: string[], enabled: boolean): UsePrevi
   return { assets, loading, ready, reload: load }
 }
 
+/**
+ * useStableArray — 数组内容稳定化 Hook
+ * 只有数组内容真正变化时才返回新的引用，避免父组件 re-render 导致的无效更新
+ */
+function useStableArray<T>(array: T[]): T[] {
+  const ref = useRef<T[]>(array)
+
+  // 比较数组内容是否真正变化
+  const hasChanged =
+    array.length !== ref.current.length || array.some((item, index) => item !== ref.current[index])
+
+  if (hasChanged) {
+    ref.current = array
+  }
+
+  return ref.current
+}
+
 export default usePreviewAssets