- setup.ts now downloads Alpine Linux minirootfs instead of Ubuntu squashfs
- Installs Alpine packages (openssh, python3, curl, ca-certificates) in chroot
- Fixes install script failing on non-Alpine base rootfs (adduser syntax)
- Clean up unused imports and lint warnings
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>