Pick branding images with the portal file chooser

omarchy-file-select gains an --extensions filter, passed through the
portal's native filters option, so the branding commands can offer
only png/svg instead of walking a find-generated menu of Pictures.

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

bin/omarchy-branding-about

@@ -8,12 +8,10 @@
 
 set -euo pipefail
 
-SOURCE_DIR="${XDG_PICTURES_DIR:-$HOME/Pictures}"
-
 case "${1:-}" in
 image)
-  image=$(omarchy-menu-file "Pick png/svg from $SOURCE_DIR" "${SOURCE_DIR}" "svg png")
-  if [[ -n $image ]] && omarchy-transcode-ascii "$image" ~/.config/omarchy/branding/about.txt --width 54 --height 26; then
+  image=$(omarchy-file-select --title "Pick PNG or SVG for About" --extensions "png svg")
+  if omarchy-transcode-ascii "$image" ~/.config/omarchy/branding/about.txt --width 54 --height 26; then
     omarchy-launch-about >/dev/null 2>&1
   fi
   ;;