Shrinking the macOS APFS container freed ~256G, but it landed at a lower
disk offset than the Linux partitions, so the ext4 root could never be
grown into it — a partition only ever extends into free space that follows
it. Rather than relocate the Asahi stub and ESP (the reliable way to brick
the boot chain), the root moved into the gap as a new partition:
p8 29424896..96687621 256.6G btrfs, subvol @, compress=zstd
zstd puts ~70G of data in ~37G, and free space went from 7.3G to 220G.
The old ext4 p5 is left intact as a rollback; generations <= 48 still boot
it, since each generation carries its own root UUID in its initrd.
Also lands the pending work in this tree: postgresql in home.packages,
the deepvis cachix substituter with a root-owned netrc, nixbuild.net as a
builder for both arches, the caffeine stay-awake unit with its SUPER+A
bind, and monthly btrfs autoScrub on the new root.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
