Breaking change from Inkscape 1.0+:
- Old syntax: inkscape input.png -o output.svg (triggers GTK init)
- New syntax: inkscape input.png --export-type=svg --export-filename=output.svg
This is the correct headless-safe approach, no need for xvfb.
Ref: https://inkscape.org/doc/inkscape-man.html
- 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
