chore: add node version to readme

Author: dragidavid

next/README.md

@@ -14,6 +14,7 @@ This is under active development, more info soon!
 
 Ensure that you isolate your workspace to the "next" folder only.
 This means:
+
 1. In your editor, open only the "next" folder.
 1. In your terminal, run commands when you are in the "next" folder only.
 
@@ -24,3 +25,17 @@ The limitation of this approach is that
 your editor will fail to recognise our git repository here.
 This also means you should turn off the editor's suggestion
 to open git repository at root.
+
+## Node.js Version
+
+This project requires Node.js LTS v22.13.1.
+We recommend using the exact version specified in `.nvmrc`:
+
+Navigate to the "next" folder and run:
+
+```bash
+nvm use
+```
+
+Without the correct Node.js version,
+tests and other development tasks will likely fail.