add demo

Author: PaddyWang

.vitepress/config.mts

@@ -51,6 +51,13 @@ export default defineConfig({
             { text: 'React新手眼中的Fiber', link: 'React新手眼中的Fiber/' },
           ],
         },
+        {
+          text: 'Demo',
+          base: '/blog/front/demo/',
+          items: [
+            { text: '视频帧渲染', link: 'video-frame/' },
+          ],
+        },
         {
           text: 'JavaScript',
           base: '/blog/front/js/',