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-launch-floating-terminal-with-presentation

@@ -8,6 +8,7 @@
 source omarchy-restart-gum
 
 cmd="$*"
-presentation_script="omarchy-show-logo; $cmd; if (( \$? != 130 )); then omarchy-show-done; fi"
+# 130 is the user bailing with Ctrl-C; anything else gets the Done/Failed prompt.
+presentation_script="omarchy-show-logo; $cmd; code=\$?; if (( code != 130 )); then omarchy-show-done \$code; fi"
 
 exec setsid uwsm-app -- xdg-terminal-exec --app-id=org.omarchy.terminal --title=Omarchy -e bash -c "$presentation_script"