Custom cache dir handling

### Description

Right now there is no documented way to set a custom cache dir for the Vite+ cache folder. The undocumented version is via an env variable.

At the same time, Vite itself has a `cachedDir` option that could be used (or mistaken by users as the desired option)

### Suggested solution

1. Add a dedicated `run.cacheDir` option
2. If it is not set, use `/task-cache` (Vite's option)
3. If that isn't set either, use the default `node_modules/.vite/task-cache` dir

To make it performant, this probably needs changes in Vite Task itself

### Alternative

_No response_

### Additional context

_No response_

### Validations

- [x] Read the [Contributing Guidelines](https://github.com/voidzero-dev/vite-plus/blob/main/CONTRIBUTING.md).
- [x] Confirm this request is for Vite+ itself and not for Vite, Vitest, tsdown, Rolldown, or Oxc.
- [x] Check that there isn't already an issue requesting the same feature.