native: install-reboot (SDL path) → ac_reboot() instead of _exit(0)
The SDL init path's post-install reboot hit `_exit(0)` after trying
sysrq-b + reboot -f. Exit code 0 tells init.sh "POWER OFF, don't
reboot", so if the reboot attempts failed, init.sh would drop into
its poweroff branch and wait forever instead of trying its own
fallback ladder (reboot -f → sysrq-b → halt -f → sysrq-c panic).
Route both install paths through ac_reboot() for consistency —
reboot(2) syscall tries UEFI ResetSystem first (reboot=efi,cold),
then systemctl/busybox reboot fallbacks, then _exit(2) which keys
init.sh's reboot branch. Matches what os.mjs's "y: reboot" flow
already does.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>