Install and Update nvm

Install or upgrade nvm from the official source using script, git, or manual methods.

Workflow

1. Identify platform and shell (macOS, Linux, WSL, Alpine; bash/zsh/fish).

2. Install via curl or wget:

   # Using curl
   curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.1/install.sh | bash
   
   # Using wget
   wget -qO- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.1/install.sh | bash