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/YamlViewer.tsx

@@ -4,6 +4,7 @@
 import { useState, useEffect, useMemo} from 'react';
 import { X, Copy, Check, Save, Loader2, Sparkles} from 'lucide-react';
 import { Button } from '@/components/ui/button';
+import { ModalOverlay } from '@/components/ui/modal-overlay';
 import { useToast } from '@/hooks/use-toast';
 import { kubernetesApi } from '@/api';
 import { cleanYAML } from './k8s-yaml-utils';
@@ -186,10 +187,13 @@ export function YamlViewer({ clusterCode, namespace, resource, name, onClose, on
     );
   }
 
-  // 弹窗模式（原有行为）
+  // 弹窗模式 — Portal 到 body，避免 PageTransition transform 导致偏移 // Logan.Li
   return (
-    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/60" onClick={onClose}>
-      <div className="bg-slate-900 border border-slate-700 rounded-xl w-[92vw] max-w-5xl h-[88vh] flex flex-col shadow-2xl" onClick={e => e.stopPropagation()}>
+    <ModalOverlay onClose={onClose}>
+      <div
+        className="bg-slate-900 border border-slate-700 rounded-xl w-[92vw] max-w-5xl 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-slate-700">
           <div>
@@ -260,6 +264,6 @@ export function YamlViewer({ clusterCode, namespace, resource, name, onClose, on
           )}
         </div>
       </div>
-    </div>
+    </ModalOverlay>
   );
 }