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.

.github/workflows/nightly-build.yml

@@ -12,8 +12,10 @@ name: Nightly ISO Build
 #
 #   https://nightly.omarchy.org/<channel>/latest.json
 #   https://nightly.omarchy.org/edge/<version>/omarchy-edge-<version>.iso
-#   https://nightly.omarchy.org/edge/<version>/vm/        base.qcow2 and what boots it
-#   https://nightly.omarchy.org/stable/<version>/<run>/vm/
+#   https://nightly.omarchy.org/edge/<version>/omarchy-edge-<version>.qcow2
+#   https://nightly.omarchy.org/edge/<version>/unpacked/    kernel, initramfs, vm-boot
+#   https://nightly.omarchy.org/stable/<version>/<run>/omarchy-<version>.qcow2
+#   https://nightly.omarchy.org/stable/<version>/<run>/unpacked/
 #
 # Nothing is published unless the ISO installed and the image passed its
 # checks. A version's files are written once and never replaced: the CDN keeps
@@ -263,17 +265,12 @@ jobs:
             echo "ok $1"
           }
           # Every file of the version, the checksum files too.
-          for iso in "$dir"/*.iso; do
-            [[ -f $iso ]] || continue
-            check "$SITE/$RELEASE/${iso##*/}" "$(cut -d" " -f1 "$iso.sha256")"
-            check "$SITE/$RELEASE/${iso##*/}.sha256" "$(sha256sum "$iso.sha256" | cut -d" " -f1)"
-          done
-          while read -r sum name; do
-            check "$SITE/$RELEASE/vm/$name" "$sum"
-          done <"$dir/vm/SHA256SUMS"
-          check "$SITE/$RELEASE/vm/SHA256SUMS" "$(sha256sum "$dir/vm/SHA256SUMS" | cut -d" " -f1)"
-          published=$(find "$dir" -type f | wc -l)
-          echo "$published files published and checked"
+          (cd "$dir" && find . -type f -printf '%P\n' | sort) >files.txt
+          [ -s files.txt ] || { echo "::error::nothing to check under $dir"; exit 1; }
+          while read -r file; do
+            check "$SITE/$RELEASE/$file" "$(sha256sum "$dir/$file" | cut -d" " -f1)"
+          done <files.txt
+          echo "$(wc -l <files.txt) files published and checked"
 
       - name: Point latest.json at it
         run: |