refactor: move useStack hook from legacy to hooks directory

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: zombieJ

assets/geek.less

@@ -84,6 +84,15 @@
       }
     }
   }
+
+  &-stack {
+    &:not(.@{notificationPrefixCls}-stack-expanded) {
+      .@{notificationPrefixCls}-list-item:nth-last-child(n + 4) {
+        opacity: 0;
+        pointer-events: none;
+      }
+    }
+  }
 }
 
 .notification-fade {

src/NotificationList.tsx

@@ -4,14 +4,14 @@ import { clsx } from 'clsx';
 import * as React from 'react';
 import type { StackConfig } from './interface';
 import { NotificationContext } from './legacy/NotificationProvider';
-import useStack from './legacy/hooks/useStack';
 import Notification, {
   type NotificationClassNames,
   type NotificationProps,
   type NotificationStyles,
 } from './Notification';
 import useListPosition from './hooks/useListPosition';
 import useListScroll from './hooks/useListScroll';
+import useStack from './hooks/useStack';
 
 export type Placement = 'top' | 'topLeft' | 'topRight' | 'bottom' | 'bottomLeft' | 'bottomRight';
 export type { StackConfig } from './interface';

src/hooks/useStack.ts

@@ -0,0 +1,24 @@
+import type { StackConfig } from '../interface';
+
+const DEFAULT_OFFSET = 8;
+const DEFAULT_THRESHOLD = 3;
+
+type StackParams = Required<StackConfig>;
+
+type UseStack = (config?: boolean | StackConfig) => [boolean, StackParams];
+
+const useStack: UseStack = (config) => {
+  const result: StackParams = {
+    offset: DEFAULT_OFFSET,
+    threshold: DEFAULT_THRESHOLD,
+  };
+
+  if (config && typeof config === 'object') {
+    result.offset = config.offset ?? DEFAULT_OFFSET;
+    result.threshold = config.threshold ?? DEFAULT_THRESHOLD;
+  }
+
+  return [!!config, result];
+};
+
+export default useStack;