0.3.1

Fixed

• Report a failed automatic sync instead of exiting 0 in silence. postinstall still never fails yarn install, but a non-zero sync (unknown saved domain, unreachable source, no Bash) now warns, so the caller's guard can react and a stale skill set is no longer mistaken for a fresh one. (#154)
• Install base skills again when a private overlay is configured. tools/sync picked its installer with an -x test, which npm and Yarn make false by dropping the executable bit when unpacking, so it fell through to the overlay's copy of tools/install — and an overlay predating base: installed no base skills while still exiting 0. (#154)