fix(k8s): YAML 弹框 Portal 到 body 修复居中偏移

PageTransition 的 transform 会使 fixed 弹框相对页面定位而非视口，
YamlViewer 尺寸较大时容易跑出可视区。统一用 ModalOverlay Portal。

frontend/src/components/kubernetes/ResourceVisualEditor.tsx

@@ -2,6 +2,7 @@
 import { useState, useEffect, useCallback } from 'react';
 import { X, Save, Loader2, Plus, Trash2, FileText, Network, Shield, Database, ChevronRight} from 'lucide-react';
 import { Button } from '@/components/ui/button';
+import { ModalOverlay } from '@/components/ui/modal-overlay';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 import { Textarea } from '@/components/ui/textarea';
@@ -132,8 +133,11 @@ export function ResourceVisualEditor({ clusterCode, namespace, resource, name, o
   const MetaIcon = meta.icon;
 
   return (
-    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/60" onClick={onClose}>
-      <div className="bg-[var(--dg-bg-primary)] border border-[var(--dg-border)] rounded-xl w-[90vw] max-w-3xl max-h-[85vh] flex flex-col shadow-2xl" onClick={e => e.stopPropagation()}>
+    <ModalOverlay onClose={onClose}>
+      <div
+        className="bg-[var(--dg-bg-primary)] border border-[var(--dg-border)] rounded-xl w-[90vw] max-w-3xl max-h-[85vh] flex flex-col shadow-2xl"
+        onClick={(e) => e.stopPropagation()}
+      >
         {/* Header */}
         <div className="flex items-center justify-between p-4 border-b border-[var(--dg-border)]">
           <div className="flex items-center gap-2">
@@ -206,7 +210,7 @@ export function ResourceVisualEditor({ clusterCode, namespace, resource, name, o
           )}
         </div>
       </div>
-    </div>
+    </ModalOverlay>
   );
 }