fix(docs): 修改默认主题：最后更新时间字段

Author: weilei

docs/src/.vuepress/config.js

@@ -8,84 +8,6 @@ module.exports = {
   ],
   themeConfig: {
     logo: '/images/logo.png',
-    lastUpdated: 'Last Updated',
-    nav: [
-      { text: '首页', link: '/' },
-      { text: '指南', link: '/guide/' },
-      { text: '组件', link: '/components/' },
-      { text: '开发计划', link: '/roadmap/' },
-      { text: '更新日志', link: '/changelog/' },
-      { text: '交流邀请', link: '/community/' },
-    ],
-    sidebar: {
-      '/guide/': [
-        {
-          title: '指南',
-          collapsable: false,
-          children: ['', 'develop', 'i18n'],
-        },
-      ],
-      '/components/': [
-        {
-          title: '组件',
-          collapsable: false,
-          children: [
-            '',
-            {
-              title: '通用',
-              collapsable: false,
-              children: ['typewriter'],
-            },
-            {
-              title: '对话类组件',
-              collapsable: false,
-              children: ['bubble', 'bubble-list'],
-            },
-            {
-              title: '交互类组件',
-              collapsable: false,
-              children: ['sender', 'attachments', 'files-card'],
-            },
-            {
-              title: '导航类组件',
-              collapsable: false,
-              children: ['conversations', 'welcome', 'prompts'],
-            },
-            {
-              title: '确认',
-              collapsable: false,
-              children: ['thinking', 'thought-chain'],
-            },
-            {
-              title: '完整应用组件',
-              collapsable: false,
-              children: ['dify-chat'],
-            },
-            {
-              title: '工具函数',
-              collapsable: false,
-              children: ['record-mixins', 'send-mixins', 'stream-mixins'],
-            },
-          ],
-        },
-      ],
-
-      '/roadmap/': [
-        {
-          title: '开发计划',
-          collapsable: false,
-          children: [''],
-        },
-      ],
-      '/changelog/': [
-        {
-          title: '更新日志',
-          collapsable: false,
-          children: [''],
-        },
-      ],
-    },
-    lastUpdated: '上次更新',
     repo: 'worryzyy/element-ui-x',
     docsDir: 'packages/docs/src',
     editLinks: true,