feat(docs): add interactive demo components for technical appendices

Add placeholder Vue components for visualizing technical concepts across multiple domains including frontend routing, browser rendering, cache design, queue design, database principles, API design, cloud services, and backend evolution. These components provide interactive educational content for the documentation.

Update documentation structure to include new appendix sections and enhance existing content with visual components. Remove unused 'codex' dependency from package.json.

docs/.vitepress/config.mjs

@@ -606,6 +606,22 @@ export default defineConfig({
                 {
                   text: '浏览器调试器',
                   link: '/zh-cn/appendix/browser-devtools'
+                },
+                {
+                  text: '浏览器渲染原理',
+                  link: '/zh-cn/appendix/browser-rendering-pipeline'
+                },
+                {
+                  text: '前端路由原理',
+                  link: '/zh-cn/appendix/frontend-routing'
+                },
+                {
+                  text: '组件状态管理',
+                  link: '/zh-cn/appendix/component-state-management'
+                },
+                {
+                  text: '前端工程化',
+                  link: '/zh-cn/appendix/frontend-engineering'
                 }
               ]
             },
@@ -617,18 +633,50 @@ export default defineConfig({
                   text: '后端进化史',
                   link: '/zh-cn/appendix/backend-evolution'
                 },
+                {
+                  text: '后端分层架构',
+                  link: '/zh-cn/appendix/backend-layered-architecture'
+                },
                 {
                   text: '后端编程语言',
                   link: '/zh-cn/appendix/backend-languages'
                 },
+                {
+                  text: '并发编程模型',
+                  link: '/zh-cn/appendix/concurrency-models'
+                },
+                {
+                  text: '接口设计规范',
+                  link: '/zh-cn/appendix/api-design'
+                },
                 { text: '数据库原理', link: '/zh-cn/appendix/database-intro' },
                 { text: '系统缓存设计', link: '/zh-cn/appendix/cache-design' },
                 { text: '消息队列设计', link: '/zh-cn/appendix/queue-design' },
                 { text: '鉴权原理与实战', link: '/zh-cn/appendix/auth-design' },
+                { text: '网关与反向代理', link: '/zh-cn/appendix/gateway-proxy' },
+                { text: '负载均衡策略', link: '/zh-cn/appendix/load-balancing' },
                 { text: '埋点设计', link: '/zh-cn/appendix/tracking-design' },
                 { text: '线上运维', link: '/zh-cn/appendix/operations' }
               ]
             },
+            {
+              text: '云计算与服务',
+              collapsed: false,
+              items: [
+                {
+                  text: '云服务基础',
+                  link: '/zh-cn/appendix/cloud-services'
+                },
+                {
+                  text: 'IAM 权限管理',
+                  link: '/zh-cn/appendix/cloud-iam'
+                },
+                {
+                  text: '对象存储与 CDN',
+                  link: '/zh-cn/appendix/cloud-storage-cdn'
+                }
+              ]
+            },
             {
               text: '通用技能',
               collapsed: false,