Add mcp.json in .vscode on "ng new my-app"

### Which @angular/* package(s) are relevant/related to the feature request?

_No response_

### Description

Creating a new Angular 21 application automatically creates the `.vscode` folder with:

```
.vscode
  extensions.json
  launch.json
  tasks.json
```

Why not also include `mcp.json`? See https://angular.dev/ai/mcp#vs-code

### Proposed solution

add `.vscode/mcp.json` on `ng new my-app`
