Why cache node_modules when prebuild command is "npm ci"?

When deploying an CRA or Next.js frontend to Amplify, the default configuration includes a prebuild command `npm ci` and cache path `node_modules/**/*`.

````yaml
version: 1
frontend:
phases:
preBuild:
commands:
- npm ci
# other stuff
cache:
paths:
- node_modules/**/*
````

However, as far as I know, `npm ci` clears `node_modules` and installs everything from scratch, which means Amplify spends time caching dependencies after each build that will simply be discarded on the next build, rendering the caching unnecessary.

Am I mistaken about this, or would it be better — and faster — to use `npm install` or just to not cache `node_modules` at all?

Start by checking the default Amplify build configuration for CRA and Next.js and verifying what npm ci does to node_modules. Done means determining whether the configured cache is useful and identifying whether the default configuration or its documentation should change.

Written by the indexing model from the issue text.