Closes#57895Closes#57896
### What?
Switch Yarn v1 to pnpm for reproduction repos, avoiding the CodeSandbox
Yarn v1 `yarn.lock` caching problem described below
### Why?
As confirmed with @CompuIves, CodeSandbox caches the `yarn.lock` file
generated after the first start + `yarn install` of a GitHub template
(Yarn v1) - this saves old versions of Next.js (not the latest canary)
in the lockfile and causes old versions of Next.js to be installed when
users click on the CodeSandbox Reproduction link during issue creation.
This leads to the current breakage, where Next.js actually cannot even
start in the reproduction sandbox:
1. Start creating a new GitHub issue on the `vercel/next` GitHub repo
2. Open [the CodeSandbox reproduction
link](https://codesandbox.io/p/sandbox/github/vercel/next.js/tree/canary/examples/reproduction-template)
linked in the **Link to the code that reproduces this issue** section
3. Observe the error message below in the `dev` task started below
(`experimental.appDir: true` was required in the `13.0.8-canary.0`
version of Next.js in the cached `yarn.lock` file, but the
`next.config.js` file no longer includes this config)
```bash
$ yarn dev
yarn run v1.22.19
$ next dev
ready - started server on 0.0.0.0:3000, url: http://localhost:3000
Error: > The `app` directory is experimental. To enable, add `appDir: true` to your `next.config.js` configuration under `experimental`. See https://nextjs.org/docs/messages/experimental-app-dir-config
at Object.findPagesDir (/project/sandbox/node_modules/next/dist/lib/find-pages-dir.js:80:19)
at new DevServer (/project/sandbox/node_modules/next/dist/server/dev/next-dev-server.js:110:59)
at NextServer.createServer (/project/sandbox/node_modules/next/dist/server/next.js:140:20)
at /project/sandbox/node_modules/next/dist/server/next.js:155:42
at async NextServer.prepare (/project/sandbox/node_modules/next/dist/server/next.js:130:24)
at async /project/sandbox/node_modules/next/dist/cli/next-dev.js:344:17
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
```
Sandbox demo:
https://codesandbox.io/p/sandbox/quirky-pascal-n32xk2?file=%2Fnext.config.js%3A5%2C1
### How?
Switch to pnpm installation commands instead of Yarn v1
### Caveats
This uses CodeSandbox-specific config
### Alternatives considered
- Delete the outdated yarn.lock file on setup of the sandbox, PR open
here: #57895
- Commit an empty `yarn.lock` file to block caching of this file, PR
open here: #57896
cc @samcx @CompuIves
## Description
This PR ensures that the default prettier config is used for examples
and templates.
This config is compatible with `prettier@3` as well (upgrading prettier
is bigger change that can be a future PR).
## Changes
- Updated `.prettierrc.json` in root with `"trailingComma": "es5"` (will
be needed upgrading to prettier@3)
- Added `examples/.prettierrc.json` with default config (this will
change every example)
- Added `packages/create-next-app/templates/.prettierrc.json` with
default config (this will change every template)
## Related
- Fixes#54402
- Closes#54409
### Reason for making this change
https://yarnpkg.com/getting-started/qa#:~:text=yarn%2Finstall%2Dstate.,your%20workspaces%20all%20over%20again.
In the official documentation of `yarn`, it is stated that `.yarn/install-state.gz` is an optimization file that developer shouldn't ever have to commit. However, currently, when running `create-next-app`, `.yarn/install-state.gz` is being commited.
### Remaining work
I apologize for only modifying one template initially to initiate the discussion first.
If this change is agreed upon, it should be synchronized with other `.gitignore` templates. Would it be possible to follow a similar approach as in https://github.com/vercel/next.js/pull/47241? I would appreciate any assistance in syncing this change.
### Updating reproduction examples
Our current `pnpm create next-app -e reproduction-template`, which is present in our Issues template, will create a Pages app. This PR updates the default (`reproduction-template`) to App Router, and adds a `reproduction-template-pages` example.
