docs: update contributor setup steps on local machine

[Ishaq101]

Describe the Issue

Description

The current dependency installation documentation does not clearly mention the required Node.js version or recommended tooling for managing Node versions.

This can cause contributors to encounter issues such as:

• ERR_PNPM_UNSUPPORTED_ENGINE
• incompatible Node.js versions during pnpm install
• confusion around setting up pnpm

Proposed Changes

Update the installation documentation to include:

• the minimum required Node.js version
• recommendation to use nvm
• corepack setup instructions for pnpm
• troubleshooting guidance for common dependency installation errors

Additional Context

New contributors may spend unnecessary time debugging environment setup issues before they can start contributing. Improving the setup documentation would make onboarding smoother and reduce common installation problems.

Affected Page

https://contribute.freecodecamp.org/how-to-work-on-the-docs-site/

Steps to Reproduce

1. Follow the local machine setup instructions from the documentation:
   https://contribute.freecodecamp.org/how-to-work-on-the-docs-site/

2. Install dependencies using:

pnpm install

3. Use a Node.js version lower than the required version (for example Node.js v20.x).

4. Observe that the installation fails with:

ERR_PNPM_UNSUPPORTED_ENGINE

Additional issue encountered on Windows PowerShell:

running scripts is disabled on this system

when attempting to run pnpm.

Recommended fix or suggestions

Update the documentation to include:

• the minimum required Node.js version

• recommendation to use a Node.js version manager such as nvm

• corepack setup instructions for pnpm

• troubleshooting guidance for common setup issues such as:

  • ERR_PNPM_UNSUPPORTED_ENGINE
  • PowerShell execution policy issues on Windows

This would help contributors complete the local machine setup more smoothly and reduce common onboarding friction.

Screenshots

The error

Lockfile is up to date, resolution step is skipped  ERR_PNPM_UNSUPPORTED_ENGINE  Unsupported environment (bad pnpm and/or Node.js version) Your Node version is incompatible with "fontkitten@1.0.1". Expected version: >=24.12.0 Got: v20.17.0 This is happening because the package's manifest has an engines.node field specified. To fix this issue, install the required Node version.