finalized Lix setup

files/scripts/install-lix.sh

@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# === INSTALL LIX FROM RPM ===
+
+rpm_url="https://nix-community.github.io/nix-installers/lix/x86_64/lix-multi-user-2.91.1.rpm"
+
+install -d /usr/share/nix-store /var/lib/nix-store /var/cache/nix-store /nix /etc/nix
+
+# Avoid systemd calls during RPM %post in the image build environment.
+export SYSTEMD_OFFLINE=1
+
+# Install the RPM; allow missing GPG key since we fetch directly by URL.
+dnf install -y --nogpgcheck "$rpm_url"
+
+
+# === ADD MISSING LIX CACHE ACCESS PUBKEY ===
+
+nix_conf=/etc/nix/nix.conf
+lix_cache_url="https://cache.lix.systems/"
+lix_cache_key="cache.lix.systems:aBnZUw8zA7H35Cz2RyKFVs3H4PlGTLawyY5KRbvJR8o="
+
+ensure_list_value() {
+  local key="$1" value="$2" escaped_value
+  escaped_value=$(printf '%s' "$value" | sed 's/[\\&]/\\&/g')
+
+  touch "$nix_conf"
+
+  if grep -Eq "^${key}[[:space:]]*=.*${escaped_value}" "$nix_conf"; then
+    return
+  fi
+
+  if grep -Eq "^${key}[[:space:]]*=" "$nix_conf"; then
+    sed -i "s|^${key}[[:space:]]*= *\\(.*\\)|${key} = \\1 ${escaped_value}|" "$nix_conf"
+  else
+    echo "${key} = ${value}" >>"$nix_conf"
+  fi
+}
+
+ensure_list_value "substituters" "$lix_cache_url"
+ensure_list_value "trusted-public-keys" "$lix_cache_key"
+
+# === MOVE INITIAL NIX STORE TO LOWERDIR ===
+
+if compgen -G "/nix/*" >/dev/null; then
+  mv /nix/* /usr/share/nix-store/
+fi