feat(post): enhance post handling with channel integration

- Updated PostHandler to include channel information in post responses.
- Introduced PostChannelBrief DTO to represent channel details associated with posts.
- Modified post conversion functions to support channel data, ensuring proper mapping of channel IDs to channel names.
- Enhanced ChannelRepository and ChannelService to facilitate batch retrieval of channels by IDs.
- Updated wire generation to inject channel service into post handler for improved functionality.

internal/dto/dto.go

@@ -120,6 +120,12 @@ type AdminUpdateUserStatusRequest struct {
 
 // ==================== Post DTOs ====================
 
+// PostChannelBrief 帖子所属频道（列表/详情卡片展示）
+type PostChannelBrief struct {
+	ID   string `json:"id"`
+	Name string `json:"name"`
+}
+
 // PostImageResponse 帖子图片响应
 type PostImageResponse struct {
 	ID              string `json:"id"`
@@ -154,6 +160,7 @@ type PostResponse struct {
 	Author         *UserResponse       `json:"author"`
 	IsLiked        bool                `json:"is_liked"`
 	IsFavorited    bool                `json:"is_favorited"`
+	Channel        *PostChannelBrief   `json:"channel,omitempty"`
 }
 
 // PostDetailResponse 帖子详情响应
@@ -179,6 +186,7 @@ type PostDetailResponse struct {
 	Author         *UserResponse       `json:"author"`
 	IsLiked        bool                `json:"is_liked"`
 	IsFavorited    bool                `json:"is_favorited"`
+	Channel        *PostChannelBrief   `json:"channel,omitempty"`
 }
 
 // ==================== Comment DTOs ====================

internal/dto/post_converter.go

@@ -31,8 +31,42 @@ func ConvertPostImagesToResponse(images []model.PostImage) []PostImageResponse {
 	return result
 }
 
-// ConvertPostToResponse 将Post转换为PostResponse（列表用）
-func ConvertPostToResponse(post *model.Post, isLiked, isFavorited bool) *PostResponse {
+func postChannelBrief(post *model.Post, channelByID map[string]*model.Channel) *PostChannelBrief {
+	if post == nil || post.ChannelID == nil || *post.ChannelID == "" || channelByID == nil {
+		return nil
+	}
+	ch := channelByID[*post.ChannelID]
+	if ch == nil {
+		return nil
+	}
+	return &PostChannelBrief{ID: ch.ID, Name: ch.Name}
+}
+
+// CollectPostChannelIDs 从帖子列表收集去重后的频道 ID（用于批量查库填充 channel 名称）
+func CollectPostChannelIDs(posts []*model.Post) []string {
+	seen := make(map[string]struct{})
+	out := make([]string, 0)
+	for _, p := range posts {
+		if p == nil || p.ChannelID == nil || *p.ChannelID == "" {
+			continue
+		}
+		id := *p.ChannelID
+		if _, ok := seen[id]; ok {
+			continue
+		}
+		seen[id] = struct{}{}
+		out = append(out, id)
+	}
+	return out
+}
+
+// PostChannelBriefForPost 根据帖子与频道映射生成频道摘要（供 Handler 手动组装响应）
+func PostChannelBriefForPost(post *model.Post, channelByID map[string]*model.Channel) *PostChannelBrief {
+	return postChannelBrief(post, channelByID)
+}
+
+// ConvertPostToResponse 将Post转换为PostResponse（列表用）；channelByID 可为 nil
+func ConvertPostToResponse(post *model.Post, channelByID map[string]*model.Channel, isLiked, isFavorited bool) *PostResponse {
 	if post == nil {
 		return nil
 	}
@@ -69,11 +103,12 @@ func ConvertPostToResponse(post *model.Post, isLiked, isFavorited bool) *PostRes
 		Author:          author,
 		IsLiked:         isLiked,
 		IsFavorited:     isFavorited,
+		Channel:         postChannelBrief(post, channelByID),
 	}
 }
 
-// ConvertPostToDetailResponse 将Post转换为PostDetailResponse
-func ConvertPostToDetailResponse(post *model.Post, isLiked, isFavorited bool) *PostDetailResponse {
+// ConvertPostToDetailResponse 将Post转换为PostDetailResponse；channelByID 可为 nil
+func ConvertPostToDetailResponse(post *model.Post, channelByID map[string]*model.Channel, isLiked, isFavorited bool) *PostDetailResponse {
 	if post == nil {
 		return nil
 	}
@@ -110,11 +145,12 @@ func ConvertPostToDetailResponse(post *model.Post, isLiked, isFavorited bool) *P
 		Author:          author,
 		IsLiked:         isLiked,
 		IsFavorited:     isFavorited,
+		Channel:         postChannelBrief(post, channelByID),
 	}
 }
 
-// ConvertPostsToResponse 将Post列表转换为响应列表（每个帖子独立检查点赞/收藏状态）
-func ConvertPostsToResponse(posts []*model.Post, isLikedMap, isFavoritedMap map[string]bool) []*PostResponse {
+// ConvertPostsToResponse 将Post列表转换为响应列表（每个帖子独立检查点赞/收藏状态）；channelByID 可为 nil
+func ConvertPostsToResponse(posts []*model.Post, channelByID map[string]*model.Channel, isLikedMap, isFavoritedMap map[string]bool) []*PostResponse {
 	result := make([]*PostResponse, 0, len(posts))
 	for _, post := range posts {
 		isLiked := false
@@ -125,21 +161,21 @@ func ConvertPostsToResponse(posts []*model.Post, isLikedMap, isFavoritedMap map[
 		if isFavoritedMap != nil {
 			isFavorited = isFavoritedMap[post.ID]
 		}
-		result = append(result, ConvertPostToResponse(post, isLiked, isFavorited))
+		result = append(result, ConvertPostToResponse(post, channelByID, isLiked, isFavorited))
 	}
 	return result
 }
 
 // BuildPostResponse 构建单个帖子响应（包含交互状态）
 // 这是一个语义化的辅助函数，便于 Handler 层调用
-func BuildPostResponse(post *model.Post, isLiked, isFavorited bool) *PostResponse {
-	return ConvertPostToResponse(post, isLiked, isFavorited)
+func BuildPostResponse(post *model.Post, channelByID map[string]*model.Channel, isLiked, isFavorited bool) *PostResponse {
+	return ConvertPostToResponse(post, channelByID, isLiked, isFavorited)
 }
 
 // BuildPostsWithInteractionResponse 批量构建帖子响应（包含交互状态）
 // 这是一个语义化的辅助函数，便于 Handler 层调用
-func BuildPostsWithInteractionResponse(posts []*model.Post, isLikedMap, isFavoritedMap map[string]bool) []*PostResponse {
-	return ConvertPostsToResponse(posts, isLikedMap, isFavoritedMap)
+func BuildPostsWithInteractionResponse(posts []*model.Post, channelByID map[string]*model.Channel, isLikedMap, isFavoritedMap map[string]bool) []*PostResponse {
+	return ConvertPostsToResponse(posts, channelByID, isLikedMap, isFavoritedMap)
 }
 
 // ==================== Comment 转换 ====================