feat(table): 表格排序与搜索改为后端处理

backend/internal/repository/channel_repo_test.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/Wei-Shaw/sub2api/internal/pkg/pagination"
 	"github.com/lib/pq"
 	"github.com/stretchr/testify/require"
 )
@@ -225,3 +226,12 @@ func TestIsUniqueViolation(t *testing.T) {
 		})
 	}
 }
+
+func TestChannelListOrderBy_AllowsDescendingIDSort(t *testing.T) {
+	params := pagination.PaginationParams{
+		SortBy:    "id",
+		SortOrder: "desc",
+	}
+
+	require.Equal(t, "c.id DESC, c.id DESC", channelListOrderBy(params))
+}