postmarketOS 25.12

As always we target the most recent Alpine release. In case of v25.12 it is the excellent Alpine Linux 3.23 and it comes with the new major version 3 of the Alpine Package Keeper, which has been released after five years (!) of development. It includes some really nice changes, such as downloading packages before installing them (which we enabled by default in postmarketOS), so that a flaky internet connection can't ever break your system again while installing updates. Another long awaited feature is logging all changes to /var/log/apk.log. See the apk3 release notes for more information.