feat: add Userland Migrations Working Group section to upgrading page

Author: edsadr

apps/site/pages/en/about/upgrading-nodejs.mdx

@@ -46,6 +46,24 @@ Take the first step and download the latest Node.js version.
 - **Dependency Incompatibility**: Critical libraries might not yet support the new Node.js version.
 - **Silent Failures**: Subtle behavior changes in the runtime can lead to difficult-to-debug issues.
 
+## Open Source Migration Tools
+
+The [Node.js Userland Migrations Working Group](https://github.com/nodejs/userland-migrations) is a community-driven initiative under the Node.js project focused on helping developers handle breaking changes gracefully. The working group maintains a collection of **codemods** — automated code transformations — that can upgrade your source code to adopt new features or adapt to breaking changes across major Node.js versions.
+
+These codemods are published in the [Codemod Registry](https://registry.codemod.com) and can be run directly against your project:
+
+```bash
+npx codemod @nodejs/<recipe>
+```
+
+Key benefits of using the Userland Migrations codemods:
+
+- **Automated refactoring**: Codemods handle repetitive, error-prone code changes across your entire codebase.
+- **Community maintained**: Recipes are built and reviewed by the Node.js community, ensuring they reflect real-world migration patterns.
+- **Incremental adoption**: Run individual recipes targeting specific breaking changes rather than attempting a full rewrite.
+
+The working group welcomes contributions — whether you want to author new codemods, review existing ones, or help shape the migration strategy for the ecosystem. Check out the [repository](https://github.com/nodejs/userland-migrations) to get involved.
+
 ## Ecosystem Support Programs
 
 The OpenJS Foundation has established an LTS Upgrade & Modernization framework to help organizations move safely off legacy and end-of-life (EOL) Node.js versions. As the nonprofit steward of Node.js, the Foundation defines the program standards, ensures alignment with the upstream project, and works with qualified service providers who deliver tools and technical support under this framework.