A trimmed port of @electron/fiddle-core that keeps
only what Electron Fiddle uses: the Installer (one immutable folder per version, safe for
several processes sharing a cache), the child environment filter and a few file helpers. It is
private, unpublished, and built from source through the fiddle-source export condition.
yarn workspace @electron/fiddle-core test # vitest, offline
yarn workspace @electron/fiddle-core typecheck