V4: store values aren't typed for derived stores

### Describe the bug

The value in a derived store is always `any` whether the dependent store(s) are implicitly or explicitly typed

```ts
derived(other, ($other, set) => 
//               ^ always "any"
```

### Reproduction

-

### Logs

_No response_

### System Info

```shell
-
```


### Severity

annoyance