Restart and update are stop + recreate — a fresh start by another name —
but only start carried the disk gate, so on a disk that shrank below the
floor after install, either action silently resumed the unprunable
Monero sync: the exact failure the gate exists to close.
Both now call check_cuprate_disk_compatibility after validate_app_id and
BEFORE any state mutation (user-stopped clear / Restarting / Updating
flip), matching handle_package_start's fail-clean contract.