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/content.go

@@ -71,10 +71,24 @@ func (s *content) List(ctx context.Context, filter *content_dto.ContentListFilte
 		return nil, errorx.ErrDatabaseError.WithCause(err)
 	}
 
+	// Fetch Prices
+	priceMap := make(map[int64]float64)
+	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
+		}
+	}
+
 	// Convert to DTO
 	data := make([]content_dto.ContentItem, len(list))
 	for i, item := range list {
-		data[i] = s.toContentItemDTO(item)
+		data[i] = s.toContentItemDTO(item, priceMap[item.ID])
 	}
 
 	return &requests.Pager{
@@ -110,6 +124,13 @@ func (s *content) Get(ctx context.Context, userID int64, id string) (*content_dt
 		return nil, errorx.ErrDatabaseError.WithCause(err)
 	}
 
+	// Fetch Price
+	var price float64
+	cp, err := models.ContentPriceQuery.WithContext(ctx).Where(models.ContentPriceQuery.ContentID.Eq(cid)).First()
+	if err == nil {
+		price = float64(cp.PriceAmount) / 100.0
+	}
+
 	// Interaction & Access status
 	isLiked := false
 	isFavorited := false
@@ -159,7 +180,7 @@ func (s *content) Get(ctx context.Context, userID int64, id string) (*content_dt
 	}
 
 	detail := &content_dto.ContentDetail{
-		ContentItem: s.toContentItemDTO(&item),
+		ContentItem: s.toContentItemDTO(&item, price),
 		Description: item.Description,
 		Body:        item.Body,
 		MediaUrls:   s.toMediaURLs(accessibleAssets),
@@ -335,7 +356,7 @@ func (s *content) GetLibrary(ctx context.Context, userID int64) ([]user_dto.Cont
 
 	var data []user_dto.ContentItem
 	for _, item := range list {
-		dto := s.toContentItemDTO(item)
+		dto := s.toContentItemDTO(item, 0)
 		dto.IsPurchased = true
 		data = append(data, dto)
 	}
@@ -420,7 +441,7 @@ func (s *content) ListTopics(ctx context.Context) ([]content_dto.Topic, error) {
 
 // Helpers
 
-func (s *content) toContentItemDTO(item *models.Content) content_dto.ContentItem {
+func (s *content) toContentItemDTO(item *models.Content, price float64) content_dto.ContentItem {
 	dto := content_dto.ContentItem{
 		ID:       cast.ToString(item.ID),
 		Title:    item.Title,
@@ -428,6 +449,7 @@ func (s *content) toContentItemDTO(item *models.Content) content_dto.ContentItem
 		AuthorID: cast.ToString(item.UserID),
 		Views:    int(item.Views),
 		Likes:    int(item.Likes),
+		Price:    price,
 	}
 	if item.Author != nil {
 		dto.AuthorName = item.Author.Nickname
@@ -600,7 +622,7 @@ func (s *content) getInteractList(ctx context.Context, userID int64, typ string)
 
 	var data []user_dto.ContentItem
 	for _, item := range list {
-		data = append(data, s.toContentItemDTO(item))
+		data = append(data, s.toContentItemDTO(item, 0))
 	}
 	return data, nil
 }