Build Pax applications for the Web

Pax applications run on the web via Web Assembly.

Install 'wasm-pack' via:
```
 curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh 
```
For Windows, follow instructions to use installer here. (opens in a new tab)

Install node v20 LTS, recommended via nvm (opens in a new tab)

# For macOS / Linux:  first install nvm
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.3/install.sh | bash

nvm install 20
nvm use 20 --default

For Windows, install nvm-windows (opens in a new tab) and install Node v20 LTS.