fix(clothes): 保护失败原因并可靠回退额度

仅属主可查看失败原因，分享只读场景置空；额度回退改用独立
ctx，避免客户端断开导致回退失败；新增 ImageProcessStatus 与
FailReason 响应字段，并抽取 detachedCtx 复用后台任务上下文。

internal/service/closet.go

@@ -172,7 +172,12 @@ func (s *ClosetShareService) Detail(ctx context.Context, userID int64, shareUUID
 	}
 	clothesResp := make([]dto.ClothesGetByUUIDResponse, 0, len(clothesList))
 	for i := range clothesList {
-		clothesResp = append(clothesResp, buildClothesResponse(&clothesList[i]))
+		item := buildClothesResponse(&clothesList[i])
+		// 非属主只读查看：不暴露内部失败原因
+		if !isOwner {
+			item.FailReason = ""
+		}
+		clothesResp = append(clothesResp, item)
 	}
 
 	// 记录接收关系：登录且非属主用户成功访问即视为收到，幂等，失败不阻断详情返回。