fix(admin): dashboard 待办卡片点击导航去重与防抖

- 同一目标路径不再重复 navigate，避免历史记录堆叠
- 400ms 冷却期内忽略重复/幽灵点击，防止来回跳转
- 新增 shouldNavigateTodoCard 守卫单元测试

apps/admin/src/pages/Dashboard/DashboardTodoCards.integration.test.ts

@@ -0,0 +1,16 @@
+import { describe, expect, it } from 'vitest';
+import { shouldNavigateTodoCard } from './DashboardTodoCards';
+
+describe('DashboardTodoCards 点击导航守卫', () => {
+  it('目标路径与当前路径不同且冷却已过时允许导航', () => {
+    expect(shouldNavigateTodoCard('/dashboard', '/attendance', 1000, 1600)).toBe(true);
+  });
+
+  it('目标路径与当前路径相同时不允许导航', () => {
+    expect(shouldNavigateTodoCard('/attendance', '/attendance', 1000, 1600)).toBe(false);
+  });
+
+  it('冷却期内忽略重复点击，防止产生多条历史记录', () => {
+    expect(shouldNavigateTodoCard('/dashboard', '/attendance', 1000, 1300)).toBe(false);
+  });
+});