Migration documentation doesn't specify Vite version required.

[AidanDaniel97]

Documentation is

• Missing
• Outdated
• Confusing
• Not sure?

Explain in Detail

I spent some time migrating our tests all the way from Vitest 2 to Vitest 4 and although everything was working in the tests and passing, I had a couple of issues

1. The vite.config.ts didn't like the test property even with <reference types="vitest/config" />
2. Upon building the application we had a blank screen with a tslib error in the console.

This seems to be because we are on "vite": "^5.4.8" which is not supported but annoyingly I only spotted this after migrating fully, and then facing issues after building - and the only place I could find this information is on the GitHub repo's [README.md](https://github.com/AidanDaniel97/vitest/blob/main/README.md) and not in the migration guide

I'm happy to submit a PR for this, I think it's a necesarry addition for some clarity on what has changed. It may also be worth doing the same for the Vitest 3 migration guide.

Your Suggestion for Changes

Ideally if we can add warning banner at the top of the migration guide

::: warning Prerequisites
Vitest 4.0 requires **Vite >= 6.0.0** and **Node >= 20.0.0**. 
:::

or more detailed

::: warning Prerequisites
Vitest 4.0 requires **Vite >= 6.0.0** and **Node >= 20.0.0**. Before proceeding
with any other migration steps, ensure your environment meets these requirements.
Running Vitest 4.0 on older versions of Vite or Node is not supported and will
likely result in unexpected errors.
:::

Reproduction

https://vitest.dev/guide/migration.html

[hi-ogawa]

Makes sense to me. This is worth calling out. Technically these are coded in package.json

vitest/packages/vitest/package.json

Line 126 in c0c0ebc

"node": "^20.0.0 || ^22.0.0 || >=24.0.0"

, but package manager doesn't highlight even for mismatch.

I think the short one is fine. For reference, I remembered Vite doc https://vite.dev/guide/migration#node-js-support

[AriPerkkio]

As Vite is required as dependency of vitest package, package managers will just happily install that required version alongside user's own vitest. And you'll end up with 2x versions of Vite, which makes the test property not recognized.

If it was defined as peerDependency, package managers would fail installation if user's version mismatched. There would be no multiple versions installed.