Consider a maintained replacement for the deep-copy test dependency

`package.json` currently declares `deep-copy@^1.4.2` as a direct dev dependency. `ts/test/test-heap-profiler.ts` loads it with `require('deep-copy')` and uses it to clone the plain profile fixtures in the heap-profiler tests.

Would the maintainers approve replacing that declaration with an npm alias?

```json
"deep-copy": "npm:@stackline/deep-copy@1.0.0"
```

The alias would preserve the existing import key and callable CommonJS API, so the test source would not need to change. The replacement supports the repository's Node `>=18` range and has no production dependencies. I maintain `@stackline/deep-copy`; its package and compatibility documentation are available at https://www.npmjs.com/package/@stackline/deep-copy and https://alexandro.net/docs/vanilla/deep-copy/contract.html.

If this direction is acceptable, I can prepare the focused manifest/lockfile change and run the heap-profiler test suite. Keeping the current version or choosing another maintained compatible implementation are also reasonable alternatives if the project prefers them.

Inizia da package.json e dal file di lock, quindi esamina ts/test/test-heap-profiler.ts per confermare l’uso esistente di require('deep-copy'). Se l’alias viene approvato, aggiorna la dichiarazione della dipendenza e il file di lock senza modificare l’import del test, quindi esegui la suite di test heap-profiler e verifica che i test passino su Node >=18.

Scritto dal modello di indicizzazione a partire dal testo della issue.