[Vitest Integration] Update guide to use Vitest 3 (#20369)

Co-authored-by: ToriLindsay <[email protected]>

Author: edmundhung

src/content/docs/agents/getting-started/testing-your-agent.mdx

@@ -23,7 +23,7 @@ The `agents-sdk-starter` template and new Cloudflare Workers projects already in
 Before you write your first test, install the necessary packages:
 
 ```sh
-npm install vitest@2.1.8 --save-dev --save-exact
+npm install vitest@~3.0.0 --save-dev --save-exact
 npm install @cloudflare/vitest-pool-workers --save-dev
 ```
 

src/content/docs/workers/testing/vitest-integration/get-started/migrate-from-miniflare-2.mdx

@@ -30,13 +30,13 @@ First, you will need to uninstall the old environment and install the new pool.
 
 ```sh
 npm uninstall vitest-environment-miniflare
-npm install --save-dev --save-exact vitest@2.1.8
+npm install --save-dev --save-exact vitest@~3.0.0
 npm install --save-dev @cloudflare/vitest-pool-workers
 ```
 
 ## Update your Vitest configuration file
 
-After installing the Workers Vitest configuration, update your Vitest configuration file to use the pool instead. Most Miniflare configuration previously specified `environmentOptions` can be moved to `poolOptions.workers.miniflare` instead. Refer to [Miniflare's `WorkerOptions` interface](https://github.com/cloudflare/workers-sdk/blob/main/packages/miniflare/README.md#interface-workeroptions) for supported options and the [Miniflare version 2 to 3 migration guide](https://miniflare.dev/get-started/migrating#api-changes) for more information. If you relied on configuration stored in a Wrangler file, set `wrangler.configPath` too.
+After installing the Workers Vitest configuration, update your Vitest configuration file to use the pool instead. Most Miniflare configuration previously specified `environmentOptions` can be moved to `poolOptions.workers.miniflare` instead. Refer to [Miniflare's `WorkerOptions` interface](https://github.com/cloudflare/workers-sdk/blob/main/packages/miniflare/README.md#interface-workeroptions) for supported options and the [Miniflare version 2 to 3 migration guide](/workers/testing/miniflare/migrations/from-v2/) for more information. If you relied on configuration stored in a Wrangler file, set `wrangler.configPath` too.
 
 ```diff
 + import { defineWorkersConfig } from "@cloudflare/vitest-pool-workers/config";

src/content/docs/workers/testing/vitest-integration/get-started/write-your-first-test.mdx

@@ -24,15 +24,15 @@ This guide will instruct you through installing and setting up the `@cloudflare/
 Open a terminal window and make sure you are in your project's root directory. Once you have confirmed that, run:
 
 ```sh
-npm install vitest@2.1.8 --save-dev --save-exact
+npm install vitest@~3.0.0 --save-dev --save-exact
 npm install @cloudflare/vitest-pool-workers --save-dev
 ```
 
 The above commands will add the packages to your `package.json` file and install them as dev dependencies.
 
 :::note
 
-Currently, the `@cloudflare/vitest-pool-workers` package _only_ works with Vitest 2.0.x - 2.1.8.
+Currently, the `@cloudflare/vitest-pool-workers` package _only_ works with Vitest 2.0.x - 3.0.x.
 
 :::
 

src/content/docs/workers/testing/vitest-integration/known-issues.mdx

@@ -34,7 +34,7 @@ Using WebSockets with Durable Objects with the [`isolatedStorage`](/workers/test
 
 When the `isolatedStorage` flag is enabled (the default), the test runner will undo any writes to the storage at the end of the test as detailed in the [isolation and concurrency documentation](/workers/testing/vitest-integration/isolation-and-concurrency/). However, Cloudflare recommends that you consider the following actions to avoid any common issues:
 
-## Await all storage operations
+#### Await all storage operations
 
 Always `await` all `Promise`s that read or write to storage services.
 
@@ -46,15 +46,15 @@ beforeAll(async () => {
 });
 ```
 
-## Explicitly signal resource disposal
+#### Explicitly signal resource disposal
 
 When calling RPC methods of a Service Worker or Durable Object that return non-primitive values (such as objects or classes extending `RpcTarget`), use the `using` keyword to explicitly signal when resources can be disposed of. See [this example test](https://github.com/cloudflare/workers-sdk/tree/main/fixtures/vitest-pool-workers-examples/rpc/test/unit.test.ts#L155) and refer to [explicit-resource-management](/workers/runtime-apis/rpc/lifecycle#explicit-resource-management) for more details.
 
 ```ts
 using result = await stub.getCounter();
 ```
 
-## Consume response bodies
+#### Consume response bodies
 
 When making requests via `fetch` or `R2.get()`, consume the entire response body, even if you are not asserting its content. For example: