Add color pixel density checks to cv_graphic_detect.py Pass 1:
- density < 20% → skip (text strokes are thin, images are filled)
- density < 30% + height < 4% page → skip (colored text line)
This fixes green headings (Insel, Internet, Inuit) being removed
as graphic regions, which also caused word reordering in lines.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>