docs: Add --yes to npx commands

[theothertomelliott]

When setting up a new repo using these instructions, I was initially confused because the Tailwind css wasn't being updated when started with make live. Hitting Ctrl+C was also hanging due to the same wait.

Adding the --yes flag allowed the commands to proceed if installation was required. I didn't add any additional explanation, but happy to include some elaboration if preferred.

[a-h]

Thanks, you're right. The commands work OK if you already have a package.json and have run npm i, but not if you're starting from scratch, and that isn't clear in the docs.