fix: K8s 集群添加缺少 code 必填字段

- KubernetesClusterDialog: 新增 code 表单字段
- 名称变更自动生成 code（小写+连字符）
- handleSubmit 增加 code 校验 + toast 提示
- payload 增加 code 字段（后端 binding:required）

frontend/src/components/kubernetes/KubernetesClusterDialog.tsx

@@ -13,9 +13,11 @@ import {
   DialogTitle,
 } from '@/components/ui/dialog';
 import { kubernetesApi } from '@/services/api';
+import { toast } from 'sonner';
 
 const emptyForm = {
   name: '',
+  code: '',
   version: '',
   description: '',
   config_type: 1, // 0=Token, 1=Kubeconfig
@@ -51,6 +53,7 @@ export function KubernetesClusterDialog({
         setHasKubeConfig(!!d.has_kube_config);
         setFormData({
           name: d.name || '',
+          code: d.code || d.name?.toLowerCase().replace(/[^a-z0-9-]/g, '-').replace(/^-+|-+$/g, '') || '',
           version: d.version || '',
           description: d.description || '',
           config_type: Number(d.config_type ?? 1),
@@ -62,6 +65,7 @@ export function KubernetesClusterDialog({
         // 降级：用列表数据
         setFormData({
           name: editingCluster.name || '',
+          code: editingCluster.code || editingCluster.name?.toLowerCase().replace(/[^a-z0-9-]/g, '-').replace(/^-+|-+$/g, '') || '',
           version: editingCluster.version || '',
           description: editingCluster.description || '',
           config_type: Number(editingCluster.config_type ?? 1),
@@ -93,11 +97,12 @@ export function KubernetesClusterDialog({
   };
 
   const handleSubmit = async () => {
-    if (!formData.name.trim()) return;
+    if (!formData.name.trim() || !formData.code.trim()) { toast.error('请填写集群名称和代码'); return; }
     try {
       setSubmitting(true);
       const payload = {
         name: formData.name,
+        code: formData.code,
         version: formData.version,
         description: formData.description,
         config_type: formData.config_type,
@@ -136,11 +141,24 @@ export function KubernetesClusterDialog({
               <Label className="text-[var(--dg-text-secondary)]">集群名称</Label>
               <Input
                 value={formData.name}
-                onChange={(e) => setFormData({ ...formData, name: e.target.value })}
+                onChange={(e) => {
+                  const name = e.target.value;
+                  const code = name.toLowerCase().replace(/[^a-z0-9-]/g, '-').replace(/^-+|-+$/g, '');
+                  setFormData({ ...formData, name, code: formData.code || code });
+                }}
                 placeholder="例如：prod-cluster"
                 className="bg-[var(--dg-bg-tertiary)] border-[var(--dg-border)] text-[var(--dg-text-primary)] placeholder:text-[var(--dg-text-muted)]"
               />
             </div>
+            <div className="space-y-2">
+              <Label className="text-[var(--dg-text-secondary)]">集群代码 (Code)</Label>
+              <Input
+                value={formData.code}
+                onChange={(e) => setFormData({ ...formData, code: e.target.value })}
+                placeholder="如: prod-cluster"
+                className="bg-[var(--dg-bg-tertiary)] border-[var(--dg-border)] text-[var(--dg-text-primary)] placeholder:text-[var(--dg-text-muted)] font-mono text-sm"
+              />
+            </div>
             <div className="space-y-2">
               <Label className="text-[var(--dg-text-secondary)]">版本（可选）</Label>
               <Input
@@ -233,7 +251,7 @@ export function KubernetesClusterDialog({
           </Button>
           <Button
             onClick={handleSubmit}
-            disabled={submitting || !formData.name.trim()}
+            disabled={submitting || !formData.name.trim() || !formData.code.trim()}
             className="bg-[var(--dg-blue)] hover:opacity-90 text-white"
           >
             {submitting ? '保存中...' : editingCluster ? '保存' : '添加'}