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.

Comienza con package.json y el archivo de bloqueo; después, inspecciona ts/test/test-heap-profiler.ts para confirmar el uso existente de require('deep-copy'). Si se aprueba el alias, actualiza la declaración de la dependencia y el archivo de bloqueo sin cambiar la importación del test; luego ejecuta la suite de tests de heap-profiler y verifica que los tests pasen en Node >=18.

Escrito por el modelo de indexación a partir del texto del issue.