set doesnt work with TZDate

My local timezone is UTC+3

```ts
const tzDate = new TZDate(date, 'Etc/GMT');
// tzDate: 2025-05-12T13:13:29.697Z
const updatedDate = set(date, { hours: 9, minutes: 0, seconds: 0, milliseconds: 0 });
// updatedDate: 2025-05-12T06:00:00.000Z
```

I expect `updatedDate` to have 9 hours, as I set the number of hours to the existing date, stripped of any knowledge of time zones.