Custom cache dir handling #2298

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 <top-level cacheDir>/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

• Read the Contributing Guidelines.
• Confirm this request is for Vite+ itself and not for Vite, Vitest, tsdown, Rolldown, or Oxc.
• Check that there isn't already an issue requesting the same feature.