fix(lint): 修复 CI 中的 ineffassign 和 unused 代码告警，修正 group 排序集成测试兼容性

backend/internal/repository/api_key_repo.go

@@ -390,7 +390,7 @@ func apiKeyListOrder(params pagination.PaginationParams) []func(*entsql.Selector
 	sortBy := strings.ToLower(strings.TrimSpace(params.SortBy))
 	sortOrder := params.NormalizedSortOrder(pagination.SortOrderDesc)
 
-	field := apikey.FieldID
+	var field string
 	switch sortBy {
 	case "name":
 		field = apikey.FieldName
@@ -402,8 +402,6 @@ func apiKeyListOrder(params pagination.PaginationParams) []func(*entsql.Selector
 		field = apikey.FieldLastUsedAt
 	case "created_at":
 		field = apikey.FieldCreatedAt
-	case "id", "":
-		field = apikey.FieldID
 	default:
 		field = apikey.FieldID
 	}

backend/internal/repository/channel_repo.go

@@ -250,7 +250,7 @@ func channelListOrderBy(params pagination.PaginationParams) string {
 	sortBy := strings.ToLower(strings.TrimSpace(params.SortBy))
 	sortOrder := strings.ToUpper(params.NormalizedSortOrder(pagination.SortOrderAsc))
 
-	column := "c.id"
+	var column string
 	switch sortBy {
 	case "":
 		column = "c.id"

backend/internal/repository/group_repo.go

@@ -319,7 +319,7 @@ func groupListOrder(params pagination.PaginationParams) []func(*entsql.Selector)
 	sortBy := strings.ToLower(strings.TrimSpace(params.SortBy))
 	sortOrder := params.NormalizedSortOrder(pagination.SortOrderAsc)
 
-	field := group.FieldSortOrder
+	var field string
 	tieField := group.FieldID
 	defaultOrder := true
 	switch sortBy {

backend/internal/repository/group_repo_sort_integration_test.go

@@ -13,11 +13,17 @@ func (s *GroupRepoSuite) TestList_DefaultSortBySortOrderAsc() {
 	s.Require().NoError(s.repo.Create(s.ctx, g1))
 	s.Require().NoError(s.repo.Create(s.ctx, g2))
 
-	groups, _, err := s.repo.List(s.ctx, pagination.PaginationParams{Page: 1, PageSize: 10})
+	groups, _, err := s.repo.List(s.ctx, pagination.PaginationParams{Page: 1, PageSize: 100})
 	s.Require().NoError(err)
-	s.Require().Len(groups, 2)
-	s.Require().Equal(g2.ID, groups[0].ID)
-	s.Require().Equal(g1.ID, groups[1].ID)
+	s.Require().GreaterOrEqual(len(groups), 2)
+	indexByID := make(map[int64]int, len(groups))
+	for i, g := range groups {
+		indexByID[g.ID] = i
+	}
+	s.Require().Contains(indexByID, g1.ID)
+	s.Require().Contains(indexByID, g2.ID)
+	// g2 has SortOrder=10, g1 has SortOrder=20; ascending means g2 comes first
+	s.Require().Less(indexByID[g2.ID], indexByID[g1.ID])
 }
 
 func (s *GroupRepoSuite) TestList_SortBySortOrderDesc() {

backend/internal/repository/promo_code_repo.go

@@ -161,7 +161,7 @@ func promoCodeListOrder(params pagination.PaginationParams) []func(*entsql.Selec
 	sortBy := strings.ToLower(strings.TrimSpace(params.SortBy))
 	sortOrder := params.NormalizedSortOrder(pagination.SortOrderDesc)
 
-	field := promocode.FieldID
+	var field string
 	switch sortBy {
 	case "bonus_amount":
 		field = promocode.FieldBonusAmount
@@ -173,8 +173,6 @@ func promoCodeListOrder(params pagination.PaginationParams) []func(*entsql.Selec
 		field = promocode.FieldCreatedAt
 	case "code":
 		field = promocode.FieldCode
-	case "id", "":
-		field = promocode.FieldID
 	default:
 		field = promocode.FieldID
 	}

backend/internal/repository/usage_log_repo.go

@@ -3812,14 +3812,12 @@ func usageLogOrderBy(params pagination.PaginationParams) string {
 	sortBy := strings.ToLower(strings.TrimSpace(params.SortBy))
 	sortOrder := strings.ToUpper(params.NormalizedSortOrder(pagination.SortOrderDesc))
 
-	column := "id"
+	var column string
 	switch sortBy {
 	case "model":
 		column = "COALESCE(NULLIF(TRIM(requested_model), ''), model)"
 	case "created_at":
 		column = "created_at"
-	case "id", "":
-		column = "id"
 	default:
 		column = "id"
 	}