fix(admin): resolve CI lint and user subscriptions regression

backend/internal/handler/admin/account_today_stats_cache.go

@@ -35,12 +35,12 @@ func buildAccountTodayStatsBatchCacheKey(accountIDs []int64) string {
 	}
 	var b strings.Builder
 	b.Grow(len(accountIDs) * 6)
-	b.WriteString("accounts_today_stats:")
+	_, _ = b.WriteString("accounts_today_stats:")
 	for i, id := range accountIDs {
 		if i > 0 {
-			b.WriteByte(',')
+			_ = b.WriteByte(',')
 		}
-		b.WriteString(strconv.FormatInt(id, 10))
+		_, _ = b.WriteString(strconv.FormatInt(id, 10))
 	}
 	return b.String()
 }

backend/internal/handler/admin/user_handler.go

@@ -86,11 +86,14 @@ func (h *UserHandler) List(c *gin.Context) {
 	}
 
 	filters := service.UserListFilters{
-		Status:               c.Query("status"),
-		Role:                 c.Query("role"),
-		Search:               search,
-		Attributes:           parseAttributeFilters(c),
-		IncludeSubscriptions: parseBoolQueryWithDefault(c.Query("include_subscriptions"), true),
+		Status:     c.Query("status"),
+		Role:       c.Query("role"),
+		Search:     search,
+		Attributes: parseAttributeFilters(c),
+	}
+	if raw, ok := c.GetQuery("include_subscriptions"); ok {
+		includeSubscriptions := parseBoolQueryWithDefault(raw, true)
+		filters.IncludeSubscriptions = &includeSubscriptions
 	}
 
 	users, total, err := h.adminService.ListUsers(c.Request.Context(), page, pageSize, filters)