feat: 添加内容创建时间字段，优化内容列表和详情视图，更新价格获取逻辑

backend/app/services/creator.go

@@ -138,7 +138,7 @@ func (s *creator) ListContents(
 	}
 
 	var list []*models.Content
-	err = q.Order(tbl.CreatedAt.Desc()).
+	err = q.Order(tbl.ID.Desc()).
 		UnderlyingDB().
 		Preload("ContentAssets").
 		Preload("ContentAssets.Asset").
@@ -148,13 +148,14 @@ func (s *creator) ListContents(
 	}
 
 	// Fetch Prices
-	ids := make([]int64, len(list))
-	for i, item := range list {
-		ids[i] = item.ID
-	}
 	priceMap := make(map[int64]float64)
-	if len(ids) > 0 {
-		prices, _ := models.ContentPriceQuery.WithContext(ctx).Where(models.ContentPriceQuery.ContentID.In(ids...)).Find()
+	if len(list) > 0 {
+		ids := make([]int64, len(list))
+		for i, item := range list {
+			ids[i] = item.ID
+		}
+		pTbl, pQ := models.ContentPriceQuery.QueryContext(ctx)
+		prices, _ := pQ.Where(pTbl.ContentID.In(ids...)).Find()
 		for _, p := range prices {
 			priceMap[p.ContentID] = float64(p.PriceAmount) / 100.0
 		}
@@ -207,6 +208,7 @@ func (s *creator) ListContents(
 			VideoCount:  videoCount,
 			AudioCount:  audioCount,
 			Status:      string(item.Status),
+			CreatedAt:   item.CreatedAt.Format("2006-01-02 15:04"),
 			IsPinned:    item.IsPinned,
 			IsPurchased: false,
 		})