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/pages/InstanceGroupPage.tsx

@@ -9,6 +9,7 @@ import { instanceApi } from '@/api/instance';
 import { userApi } from '@/api/user';
 import { useActionPermission } from '@/hooks/useAuth';
 import { ConfirmDialog } from '@/components/ConfirmDialog';
+import { ModalOverlay } from '@/components/ModalOverlay';
 
 /* ───────── Constants ───────── */
 
@@ -389,8 +390,8 @@ export default function InstanceGroupPage() {
 
       {/* Form Modal (create & edit) */}
       {formMode && (
-        <div className="fixed inset-0 z-[100] flex items-start justify-center pt-[5vh] bg-black/60 backdrop-blur-sm">
-          <div className="w-full max-w-3xl bg-[var(--dg-bg-primary)] rounded-xl shadow-2xl flex flex-col max-h-[90vh] border border-[var(--dg-border)]" onClick={e => e.stopPropagation()}>
+        <ModalOverlay open={!!formMode} onClose={formClose} width="max-w-3xl">
+          <div className="w-full max-w-3xl bg-[var(--dg-bg-primary)] rounded-xl shadow-2xl flex flex-col max-h-[90vh] border border-[var(--dg-border)]">
             <div className="flex items-center justify-between px-6 py-4 border-b border-[var(--dg-border)]">
               <h3 className="text-lg font-semibold">{formMode === 'create' ? '新建权限策略' : '编辑权限策略'}</h3>
               <button onClick={formClose} className="p-1.5 rounded-lg hover:bg-[var(--dg-bg-hover)] text-[var(--dg-text-muted)] hover:text-[var(--dg-text-primary)] transition-colors"><X className="w-4 h-4" /></button>
@@ -433,7 +434,7 @@ export default function InstanceGroupPage() {
               </div>
             </div>
           </div>
-        </div>
+        </ModalOverlay>
       )}
 
       <ConfirmDialog
@@ -447,8 +448,8 @@ export default function InstanceGroupPage() {
 
       {/* User Modal */}
       {showUserModal && (
-        <div className="fixed inset-0 z-[100] flex items-start justify-center pt-[10vh] bg-black/60 backdrop-blur-sm">
-          <div className="w-full max-w-md bg-[var(--dg-bg-primary)] rounded-xl shadow-2xl border border-[var(--dg-border)]" onClick={e => e.stopPropagation()}>
+        <ModalOverlay open={showUserModal} onClose={() => setShowUserModal(false)} width="max-w-md">
+          <div className="w-full max-w-md bg-[var(--dg-bg-primary)] rounded-xl shadow-2xl border border-[var(--dg-border)]">
             <div className="flex items-center justify-between px-6 py-4 border-b border-[var(--dg-border)]">
               <h3 className="text-lg font-semibold">关联用户</h3>
               <button onClick={() => setShowUserModal(false)} className="p-1.5 rounded-lg hover:bg-[var(--dg-bg-hover)] text-[var(--dg-text-muted)] hover:text-[var(--dg-text-primary)] transition-colors"><X className="w-4 h-4" /></button>
@@ -474,7 +475,7 @@ export default function InstanceGroupPage() {
             </div>
             </div>{/* end px-6 py-4 */}
           </div>
-        </div>
+        </ModalOverlay>
       )}
     </div>
   );