Replace fs-extra ensureDir/mkdirp/mkdirs with fs.mkdir

Replaces fs-extra's ensureDir, mkdirp, and mkdirs (and their Sync variants) with mkdir/mkdirSync from node:fs/promises and node:fs, passing { recursive: true } as fs-extra does internally. A numeric mode or an options object's mode carries over; the callback form maps to the callback mkdir from node:fs. Options that can't be read statically are left alone.