package_upgrade job streams apt-get output into the job log (streaming
CommandRunner, DebianUpdater with dist-upgrade or --only-upgrade), refreshes
the inventory afterwards and flags reboot-required. POST /api/system/upgrade
(admin), package name validation, selectable package table with confirm
dialog and live log on the Updates page. Fake updater for dev.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>