按需引入 f2 时，缺少 TypeScript 类型声明

- [ ] I have searched the [issues](https://github.com/antvis/f2/issues) of this repository and believe that this is not a duplicate.

### What problem does this feature solve?
当通过 `import F2 from '@antv/f2/lib/core';` 引入时，TypeScript 会报告说没有找到合适的类型声明。
简单阅读了一下项目中 types 目录的代码，应该没有考虑过对于按需引入时的支持。
建议补足以优化 TypeScript 下的使用体验。

### What does the proposed API look like?
对于按需引入相关的官方示例代码（https://f2.antv.vision/zh/docs/tutorial/require），都有良好的 TypeScript 类型声明支持。

Start by reviewing the repository's types directory and the official on-demand import examples at https://f2.antv.vision/zh/docs/tutorial/require. Check how the `@antv/f2/lib/core` import is exposed to TypeScript, and consider the work complete when those examples have usable type declarations without the reported missing-declaration error.

Written by the indexing model from the issue text.