Generate projects with `engine-strict` by default

### Command

new

### Description

It is quite easy to install a package incompatible with the current Node runtime. NPM only emits a warning by default which is easily overlooked. Once the package is installed, running it may result in unpredictable behavior, or might even work in the short term and then suddenly fail seemingly randomly in the future due to unrelated updates or changes to executed code paths which suddenly become incompatible with the currently installed Node version.

### Describe the solution you'd like

New projects should generate an `.npmrc` with `engine-strict=true` by default when using NPM as the package manager.

https://docs.npmjs.com/cli/v11/using-npm/config#engine-strict

This opts-in to a stricter environment which emits a hard error when installing a package incompatible with the current Node environment.

Yarn and pnpm already use the strict behavior by default, so this aligns with the broader direction of the package manager ecosystem.

Spin off from https://github.com/angular/angular-cli/issues/30547.

Beginne mit dem `new`-Befehl und verfolge, wie sich generierte Projektdateien je nach Paketmanager unterscheiden, wobei der angeforderte `.npmrc`-Output im Mittelpunkt steht. Bestätige, dass neue Projekte mit NPM eine `.npmrc` mit `engine-strict=true` erzeugen, während andere Paketmanager unverändert bleiben, und überprüfe das Verhalten mit den relevanten Generierungstests.

Vom Indexierungsmodell aus dem Issue-Text verfasst.