packages(arch): route byobu through yay (AUR-only); split official vs AUR lists so pacman --needed can't abort on a missing target; as_user prefers TARGET_USER for AUR builds

lib/log.sh

@@ -9,12 +9,13 @@ ok()   { printf '\033[1;32mok\033[0m %s\n' "$*"; }
 # run a command as root when not already root
 sudo_() { if (( EUID == 0 )); then "$@"; else sudo "$@"; fi; }
 
-# run a command AS the invoking (non-root) user — used for AUR builds, etc.
-# when root: drop to SUDO_USER (or USER) via runuser; when not root: run directly.
+# run a command AS the target non-root user — used for AUR builds, nvm, etc.
+# precedence (when running as root): TARGET_USER (set by create-user) > SUDO_USER > USER.
+# when not root: run directly as ourselves.
 as_user() {
-  local u="$USER"
+  local u="${SUDO_USER:-$USER}"
   if (( EUID == 0 )); then
-    u="${SUDO_USER:-$USER}"
+    u="${TARGET_USER:-${SUDO_USER:-$USER}}"
     command -v runuser >/dev/null 2>&1 && runuser -u "$u" -- "$@" || su "$u" -c "$*"
   else
     "$@"