Objects whose lineweight resolves to Default were always drawn and
plotted at 0.25 mm. They now use LWDEFAULT (hundredths of a mm, 0..211),
falling back to 0.25 mm when it is unset or out of range. All backends
(canvas, PNG, SVG, PDF) read the width from the display list.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
