feat: 添加新的 Sakai Vue 布局和样式，重构基础样式，更新 README，调整插件配置

vite.config.plugins.ts

@@ -49,7 +49,7 @@ export function Plugins() {
     }), // https://vue-macros.dev/zh-CN/guide/bundler-integration.html
 
     // https://github.com/JohnCampionJr/vite-plugin-vue-layouts?tab=readme-ov-file#configuration
-    Layouts({ pagesDirs: [] }),
+    Layouts({ pagesDirs: [], defaultLayout: 'sakai-vue/AppLayout' }),
 
     // https://github.com/antfu/unocss
     // see uno.config.ts for config