fix: 删除操作清理远端资源并拦截悬空引用

- 部署删除: k8s 模式清理 StatefulSet/Service/ConfigMap 与 PVC，先卸载关联采集器
- 采集器删除: 同步卸载成功后再删记录，失败保留避免孤儿
- 集群/存储/主机删除: 有部署或采集器引用时拒绝，避免悬空外键
- Token RBAC 补 services/proxy，保证 cluster-svc 数据源可查询

frontend/src/pages/clusters/components/ClusterFormDialog.tsx

@@ -299,7 +299,7 @@ metadata:
   namespace: log
 rules:
   - apiGroups: [""]
-    resources: ["pods", "pods/log", "services", "configmaps", "secrets", "persistentvolumeclaims", "events", "serviceaccounts"]
+    resources: ["pods", "pods/log", "services", "services/proxy", "configmaps", "secrets", "persistentvolumeclaims", "events", "serviceaccounts"]
     verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
   - apiGroups: ["apps"]
     resources: ["statefulsets", "daemonsets", "deployments"]