VM image: one file, named like the ISO

The image was a folder, vm/, holding base.qcow2 and what boots it. It is
now one file next to the ISO, with the ISO's name and its own checksum
file, the way Ubuntu, Debian, Arch, Fedora and CentOS publish theirs:

  edge/<version>/omarchy-edge-<version>.qcow2
  stable/<version>/<run>/omarchy-<version>.qcow2

The image boots by itself through UEFI. What a direct boot needs, the
kernel, initramfs, kernel arguments and vm-boot, is in an unpacked/
folder beside it, Ubuntu's name for the same thing. The firmware
variables are no longer published: a boot with the firmware's defaults
finds the disk.

latest.json follows: vm.url, vm.sha256 and vm.size are the image, as
url, sha256 and size are the ISO; vm.unpacked and vm.unpacked_files are
the folder. vm-boot takes the image file. The publish job compares every
file it uploaded, whatever the layout. README, tests and the workflow's
header say the same.

test/vm-image/vm-seal

@@ -7,10 +7,9 @@
 #
 # installed_dir holds base.qcow2, OVMF_VARS.4m.fd and id_ed25519, which is
 # what test/integration leaves in test-runs/<iso>-integration once its install
-# has passed. sealed_dir gets a standalone, zstd-compressed base.qcow2, the
-# firmware variables that boot it through UEFI, and the UKI's vmlinuz, initrd
-# and cmdline for booting it directly. It holds no key: each boot is handed
-# one (see vm-boot).
+# has passed. sealed_dir gets a standalone, zstd-compressed base.qcow2, which
+# boots by itself through UEFI, and the UKI's vmlinuz, initrd and cmdline for
+# booting it directly. It holds no key: each boot is handed one (see vm-boot).
 #
 # The image keeps the installer's user and password (GUEST_PASSWORD, default
 # omarchy) for the desktop and sudo. SSH takes keys only.
@@ -145,8 +144,5 @@ tr -d '\0' <"$state/cmdline" | tr ' ' '\n' | { grep -vE '^(resume|resume_offset)
 
 # zstd clusters: QEMU reads them as they are, so the download boots as it is.
 qemu-img convert -c -O qcow2 -o compression_type=zstd -m 16 -W "$state/edit.qcow2" "$out/base.qcow2"
-# The variables hold the boot entry the installer registered; a firmware boot
-# of this disk needs them, a direct kernel boot does not.
-cp "$in/OVMF_VARS.4m.fd" "$out/OVMF_VARS.4m.fd"
-( cd "$out" && sha256sum base.qcow2 OVMF_VARS.4m.fd vmlinuz initrd cmdline >SHA256SUMS )
+( cd "$out" && sha256sum base.qcow2 vmlinuz initrd cmdline >SHA256SUMS )
 echo "sealed: $out ($(du -sh "$out/base.qcow2" | cut -f1)); cmdline: $(cat "$out/cmdline")"