Review fixes for 11.4 and 11.4b

ubuntu.sh takes Ubuntu 24.04 and its derivatives alone, since the DEB
names 24.04's t64 libraries. nixos.sh installs the newest release's
tag, not main. The release workflow refuses a tag that names another
version than the build files, and runs on the Node 24 actions.
DistortTests pins Swift's division by w past the horizon.

Co-Authored-By: Claude <noreply@anthropic.com>

scripts/install/nixos.sh

@@ -9,4 +9,14 @@ if [ "$(uname -m)" != x86_64 ]; then
     echo "OmaPhoto's flake builds for x86_64 alone." >&2
     exit 1
 fi
-nix --extra-experimental-features "nix-command flakes" profile install github:ZacharyZhang-NY/OmaPhoto
+# The newest release's tag, as GitHub redirects to it.
+latest=$(curl -fsSLI --proto '=https' -o /dev/null -w '%{url_effective}' https://github.com/ZacharyZhang-NY/OmaPhoto/releases/latest)
+tag=${latest##*/}
+case "$tag" in
+v[0-9]*) ;;
+*)
+    echo "No release found at $latest." >&2
+    exit 1
+    ;;
+esac
+nix --extra-experimental-features "nix-command flakes" profile install "github:ZacharyZhang-NY/OmaPhoto/$tag"

scripts/install/ubuntu.sh

@@ -1,16 +1,14 @@
 #!/usr/bin/env bash
-# Installs OmaPhoto's latest DEB on Ubuntu and its derivatives.
+# Installs OmaPhoto's latest DEB on Ubuntu 24.04 and derivatives.
 set -euo pipefail
 base=https://github.com/ZacharyZhang-NY/OmaPhoto/releases/latest/download
 package=omaphoto_amd64.deb
 . /etc/os-release
-case " ${ID:-} ${ID_LIKE:-} " in
-*" ubuntu "*) ;;
-*)
-    echo "This script is for Ubuntu and its derivatives; this system is ${PRETTY_NAME:-unknown}." >&2
+# The DEB names Ubuntu 24.04's libraries; derivatives name their base.
+if [ "${UBUNTU_CODENAME:-}" != noble ]; then
+    echo "This script is for Ubuntu 24.04 and systems built on it; this system is ${PRETTY_NAME:-unknown}." >&2
     exit 1
-    ;;
-esac
+fi
 if [ "$(uname -m)" != x86_64 ]; then
     echo "OmaPhoto's packages are built for x86_64 alone." >&2
     exit 1