feat: 路由改名/kubectl预装/导出YAML精简/Service标签页优化/Alpine镜像源换清华

- 路由 /deploy/credentials → /deploy/configureTools
- kubectl 改为预装(Dockerfile) + 种子数据 preinstall
- 导出YAML精简: Service/Ingress/Deployment 全面清理运行时字段
- DeploymentEditService 只显示匹配 selector 的关联 Service
- Alpine 镜像源 mirrors.aliyun.com → mirrors.tuna.tsinghua.edu.cn

backend/pkg/kubernetesclient/client.go

@@ -290,10 +290,16 @@ type DeploymentItem struct {
 
 type DeploymentSpec struct {
 	Replicas int                `json:"replicas"`
+	Selector *LabelSelector     `json:"selector,omitempty"` // matchLabels — 前端 Service 关联用
 	Template DeploymentTemplate `json:"template"`
 	Paused   bool               `json:"paused"`
 }
 
+// LabelSelector K8s 标签选择器
+type LabelSelector struct {
+	MatchLabels map[string]string `json:"matchLabels,omitempty"`
+}
+
 type DeploymentTemplate struct {
 	Spec PodSpec `json:"spec"`
 }