Ability to manually specify locale in SSR

### Description

There is no way to specify locale in [`AngularAppEngine#handle`](https://github.com/angular/angular-cli/blob/19.0.0/packages/angular/ssr/src/app-engine.ts#L65-L69) based on [`Accept-Language`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language), [`Cookie`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cookie), etc. The current implementation of [`AngularAppEngine`](https://github.com/angular/angular-cli/blob/19.0.0/packages/angular/ssr/src/app-engine.ts#L24) chooses locale based on URL.

### Describe the solution you'd like

Ability to specify an array of locales when calling `handle`:

```diff
app.use('/**', (req, res, next) => {
angularApp
- .handle(req)
+ .handle(req, undefined, { locales: req.acceptsLanguages() })
.then((response) =>
response ? writeResponseToNodeResponse(response, res) : next(),
)
```

As far as I understand, this will also require removing the locale prefix from ``.

### Describe alternatives you've considered

_No response_

Start with packages/angular/ssr/src/app-engine.ts, especially AngularAppEngine#handle and its current URL-based locale selection. Trace how the locale reaches the rendered document, then verify that callers can provide an ordered locale array from request data and that the resulting does not retain an unwanted locale prefix.

Written by the indexing model from the issue text.