Add Installation guide for Windows users (Fixes #3730)

[Irfan762]

Adds a Windows-specific installation guide below the Manual Installation section to improve accessibility for Windows users and beginners.

Includes direct Node.js installation steps, command alternatives, and environment setup instructions.

Fixes #3730

[Irfan762]

@cassiano Could you please review and merge my request?

[cassiano]

@cassiano Could you please review and merge my request?

I am sorry. I don't even have a Windows environment available to validate this. In addition, I don't have the rights to merge requests.

[Irfan762]

Hi @cassiano,

Thank you for your response. I understand 👍

Could you please let me know who would be the right maintainer/reviewer to look into this PR?

Thanks again for your time!

[cassiano]

@raclim should be able to assist you.

[Irfan762]

@raclim Could you please review and merge my request?

[yugalkaushik]

@Irfan762 https://github.com/processing/p5.js-web-editor/blob/develop/contributor_docs/installation.md The installation guide applies to all environments (macOS, Linux, and Windows). The setup steps remain the same across platforms and any OS-specific differences are already mentioned where required. The only command that changes for Windows is using copy instead of cp, all other setup instructions remain identical. This change is not required right now, but if you’d like, you can open a separate PR to include the copy command for Windows users.