Need better `eject`

### Prerequisites

- [X] I have written a descriptive issue title
- [X] I have searched existing issues to ensure the feature has not already been requested

### 🚀 Feature Proposal

- [ ] it's unintuitive (for me at least) to have to imperatively declare `--esm` to `fastify eject` when using js/esm combination.
Like, when I'm already cd-ed into the dir, and eject is using `process.cwd()`, meaning it can also lookup pkg json and see what's there.
- [ ] other point is that scripts stay bound to CLI, I expect to have scripts overwritten to something like `"start" : "node server.js"` | `"dev" : "node --watch server.js"` at least in js case.

- [ ] bonus points if CLI would have removed itself from dependencies, and dumped that test helper into tests directory

### Motivation

I don't have to massage the generated project too much after `eject`

### Example

_No response_

Inizia dal punto di ingresso della CLI `fastify eject` e verifica come utilizza `process.cwd()` e i metadati del pacchetto. Esamina gli script generati, la gestione delle dipendenze e la directory dei test. Il lavoro è completato quando eject è in grado di dedurre la configurazione JavaScript/ESM, produrre gli script richiesti e gestire la pulizia opzionale e il comportamento dell’helper per i test.

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