USB drives: yazi g m, udiskie Open → yazi

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

settings/desktop.nix

@@ -67,6 +67,9 @@
         enable = true;
         automount = false;
         tray = "never";
+        # "Open" button → yazi (Super+E's spelling; udiskie appends the path).
+        settings.program_options.file_manager =
+          "${pkgs.ghostty}/bin/ghostty +new-window --working-directory=/home/fred -e yazi";
       };
 
       dconf.settings."org/nemo/window-state".start-with-menu-bar = false;