fix: 接通服务器V2排序链路

- 将排序参数从V2 Handler传递至Service与Repository

- 增加仓储分页排序与参数白名单测试

backend/repository/server_sort_test.go

@@ -0,0 +1,57 @@
+package repository
+
+import (
+	"testing"
+
+	"ezops/model"
+
+	"github.com/glebarez/sqlite"
+	"gorm.io/gorm"
+)
+
+// TestServerRepositoryListHostnameOrder 验证实际服务器仓储按主机名分页排序。 // Logan.Li
+func TestServerRepositoryListHostnameOrder(t *testing.T) {
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("打开测试数据库失败: %v", err)
+	}
+	if err := db.AutoMigrate(&model.Server{}, &model.Region{}, &model.Cloud{}); err != nil {
+		t.Fatalf("迁移测试表失败: %v", err)
+	}
+	for _, hostname := range []string{"test-win", "c-windows", "alpha-host"} {
+		if err := db.Create(&model.Server{Hostname: hostname, IP: "127.0.0.1"}).Error; err != nil {
+			t.Fatalf("创建测试服务器失败: %v", err)
+		}
+	}
+
+	repo := NewServerRepository(db)
+	servers, total, err := repo.List("", "", "", "hostname", "asc", 1, 10)
+	if err != nil {
+		t.Fatalf("查询测试服务器失败: %v", err)
+	}
+	if total != 3 || len(servers) != 3 {
+		t.Fatalf("服务器数量异常 total=%d len=%d", total, len(servers))
+	}
+	if servers[0].Hostname != "alpha-host" || servers[2].Hostname != "test-win" {
+		t.Fatalf("主机名升序结果异常: %q, %q, %q", servers[0].Hostname, servers[1].Hostname, servers[2].Hostname)
+	}
+}
+
+// TestServerOrderClause 验证非法排序参数无法进入 SQL 表达式。 // Logan.Li
+func TestServerOrderClause(t *testing.T) {
+	tests := []struct {
+		sortField string
+		sortOrder string
+		want      string
+	}{
+		{want: "created_at DESC"},
+		{sortField: "hostname", sortOrder: "asc", want: "LOWER(hostname) ASC, id ASC"},
+		{sortField: "hostname", sortOrder: "desc", want: "LOWER(hostname) DESC, id DESC"},
+		{sortField: "hostname; DROP TABLE asset_servers", sortOrder: "asc", want: "created_at DESC"},
+	}
+	for _, tt := range tests {
+		if got := serverOrderClause(tt.sortField, tt.sortOrder); got != tt.want {
+			t.Fatalf("serverOrderClause(%q, %q) = %q, want %q", tt.sortField, tt.sortOrder, got, tt.want)
+		}
+	}
+}