feat: improve Example App

The Example app currently uses a Drawer(deprecated component) for navigation and a simple list based navigation to go each component showcase.
This could be improved by:
- replacing the drawer with a more modern UI like a modal sheet for global configuration of theme configuration
- adding a search functionality
- a main "sample" section when the user first opens the app showcasing a mix of different components like on https://oss.callstack.com/react-native-paper/ or https://material-foundation.github.io/material-theme-builder/

首先检查 Example 应用当前的 Drawer 导航和组件展示列表，然后查看链接的参考应用，了解可能的方向。完成标准是确定一个一致认可的设计，用于替换已弃用的导航、添加搜索功能，并在首次启动时提供一个混合示例部分。

由索引模型根据 Issue 内容生成。