When union columns from multiple content zones are applied, column
boundaries can span wider than any single zone's bbox. Using
zone.bbox_px.w as the scale reference caused the total scaled width
to exceed the container, pushing the table off-screen.
Now uses the actual total column width sum as the scale reference,
guaranteeing columns always fit within the container.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
fd79d5e4fa