- Inkscape requires X11 display connection, causing 'GtkStyleContext without display' error
- Solution: use xvfb-run to create virtual X11 display
- Fallback: try direct inkscape if xvfb-run fails
- Add xvfb package to Dockerfile
- Update inkscape tests for new xvfb-run behavior
Fixes: Gtk-ERROR: Can't create a GtkStyleContext without a display connection