Show a failure state when a presented command exits non-zero

The floating-terminal presentation wrapper showed the green "Done!"
prompt for every exit code except Ctrl-C, so a failed update or channel
switch closed looking like a success. Pass the command's exit code
through to omarchy-show-done and render a red "Failed (exit code N)!"
prompt when it is non-zero. The pkg install/remove pickers get the same
treatment.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bin/omarchy-pkg-remove

@@ -20,5 +20,5 @@ pkg_names=$(yay -Qqe | fzf "${fzf_args[@]}")
 if [[ -n $pkg_names ]]; then
   # Convert newline-separated selections to space-separated for yay
   echo "$pkg_names" | tr '\n' ' ' | xargs sudo pacman -Rns --noconfirm
-  omarchy-show-done
+  omarchy-show-done $?
 fi