docs: link migration guide from quick start

Author: chenjiahan

website/docs/en/guide/quick-start.mdx

@@ -105,6 +105,10 @@ Options:
 Available templates: app-vanilla, app-vanilla-ts, app-react, app-react-ts, app-preact, app-preact-ts, app-vue, app-vue-ts, app-lit, app-lit-ts, app-svelte, app-svelte-ts, app-solid, app-solid-ts, lib-node, lib-node-ts, lib-react, lib-react-ts, lib-vue, lib-vue-ts, lib-svelte, lib-svelte-ts, lib-solid, lib-solid-ts, doc, doc-i18n, turborepo
 ```
 
+## Migrate an existing project
+
+To migrate an existing project to Rstack CLI, see the [migration guide](./migration) for supported tools and how to use the migration skill.
+
 ## Install Rstack CLI \{#install-rstack}
 
 Install [`rstack`](https://www.npmjs.com/package/rstack) as a development dependency in a project that has a `package.json`:

website/docs/zh/guide/quick-start.mdx

@@ -105,6 +105,10 @@ Options:
 Available templates: app-vanilla, app-vanilla-ts, app-react, app-react-ts, app-preact, app-preact-ts, app-vue, app-vue-ts, app-lit, app-lit-ts, app-svelte, app-svelte-ts, app-solid, app-solid-ts, lib-node, lib-node-ts, lib-react, lib-react-ts, lib-vue, lib-vue-ts, lib-svelte, lib-svelte-ts, lib-solid, lib-solid-ts, doc, doc-i18n, turborepo
 ```
 
+## 迁移现有项目 \{#migrate-an-existing-project}
+
+如需将现有项目迁移到 Rstack CLI，请参阅[迁移指南](./migration)，了解支持的工具和迁移 Skill 的使用方式。
+
 ## 安装 Rstack CLI \{#install-rstack}
 
 在已有 `package.json` 的项目中，将 [`rstack`](https://www.npmjs.com/package/rstack) 安装为开发依赖：