fix: 统一弹框组件 — ModalOverlay对齐EditInstanceDialog行为

- ModalOverlay移除遮罩层onClick(不响应外部点击关闭)
- 移除body.style.overflow=hidden(修复白条问题)
- max-h从90vh改为85vh(与EditInstanceDialog一致)
- 10个页面手写fixed弹框替换为ModalOverlay组件
- InstanceGroupPage/WorkflowPage/UsersPage/RedisDetailPage/TicketsPage已替换
- dialog.tsx添加onPointerDownOutside/onInteractOutside阻止外部点击
- index.css添加body[data-scroll-locked]覆盖Radix滚动锁定
- Layout.tsx main添加relative定位上下文

frontend/src/components/Layout.tsx

@@ -122,7 +122,7 @@ export default function Layout() {
       </aside>
 
       {/* 主内容区 */}
-      <main className="flex-1 flex flex-col min-w-0 overflow-hidden">
+      <main id="app-main" className="relative flex-1 flex flex-col min-w-0 overflow-hidden">
         {/* 顶部栏 */}
         <header className="h-14 bg-[var(--dg-bg-secondary)] border-b border-[var(--dg-border)] flex items-center justify-between px-5 flex-shrink-0">
           {/* Breadcrumb area */}

frontend/src/components/ModalOverlay.tsx

@@ -0,0 +1,40 @@
+import { useEffect, useCallback } from 'react';
+
+interface ModalOverlayProps {
+  open: boolean;
+  onClose: () => void;
+  width?: string;
+  className?: string;
+  children: React.ReactNode;
+}
+
+export function ModalOverlay({ open, onClose, width = 'max-w-lg', className = '', children }: ModalOverlayProps) {
+  const handleKeyDown = useCallback(
+    (e: KeyboardEvent) => {
+      if (e.key === 'Escape') onClose();
+    },
+    [onClose],
+  );
+
+  useEffect(() => {
+    if (open) {
+      document.addEventListener('keydown', handleKeyDown);
+    }
+    return () => {
+      document.removeEventListener('keydown', handleKeyDown);
+    };
+  }, [open, handleKeyDown]);
+
+  if (!open) return null;
+
+  return (
+    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 backdrop-blur-sm">
+      <div
+        className={`bg-[var(--dg-bg-secondary)] rounded-xl shadow-2xl w-full ${width} max-h-[85vh] overflow-y-auto ${className}`}
+        onClick={(e) => e.stopPropagation()}
+      >
+        {children}
+      </div>
+    </div>
+  );
+}

frontend/src/components/ui/dialog.tsx

@@ -36,7 +36,9 @@ function DialogOverlay({
     <DialogPrimitive.Overlay
       data-slot="dialog-overlay"
       className={cn(
-        "data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 fixed inset-0 z-50 bg-black/50",
+        "fixed inset-0 z-[100] bg-black/50",
+        "data-[state=open]:animate-in data-[state=closed]:animate-out",
+        "data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0",
         className
       )}
       {...props}
@@ -53,12 +55,24 @@ function DialogContent({
   showCloseButton?: boolean
 }) {
   return (
-    <DialogPortal data-slot="dialog-portal">
+    <DialogPortal>
       <DialogOverlay />
       <DialogPrimitive.Content
         data-slot="dialog-content"
+        onPointerDownOutside={(e) => {
+          e.preventDefault()
+        }}
+        onInteractOutside={(e) => {
+          e.preventDefault()
+        }}
         className={cn(
-          "bg-background data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 fixed top-[50%] left-[50%] z-50 grid w-full max-w-[calc(100%-2rem)] translate-x-[-50%] translate-y-[-50%] gap-4 rounded-lg border p-6 shadow-lg duration-200 outline-none sm:max-w-lg",
+          "bg-background data-[state=open]:animate-in data-[state=closed]:animate-out",
+          "data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0",
+          "data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95",
+          "fixed z-[101] grid w-full max-w-[calc(100%-2rem)]",
+          "top-[50%] left-[50%] translate-x-[-50%] translate-y-[-50%]",
+          "gap-4 rounded-lg border p-6 shadow-lg duration-200",
+          "outline-none sm:max-w-lg",
           className
         )}
         {...props}