docs: add document minimum Node.js version for CLI (supabase#40866)

* docs: add document minimum Node.js version for CLI

* Update apps/docs/content/guides/local-development/cli/getting-started.mdx

* Update apps/docs/content/guides/local-development/cli/getting-started.mdx

* Update apps/docs/content/guides/local-development/cli/getting-started.mdx

---------

Co-authored-by: Chris Chinchilla <[email protected]>

Author: magentaqin

apps/docs/content/guides/local-development/cli/getting-started.mdx

@@ -66,6 +66,12 @@ Run the CLI by prefixing each command with `npx` or `bunx`:
 npx supabase --help
 ```
 
+<Admonition type="caution">
+
+The Supabase CLI requires **Node.js 20 or later** when run via `npx` or `npm`. Older Node.js versions, such as 16, are not supported and fail to start the CLI.
+
+</Admonition>
+
 You can also install the CLI as dev dependency via [npm](https://www.npmjs.com/package/supabase):
 
 ```sh