With the view turned 90 or 270 degrees, the page's screen rectangle has
its sides swapped, so xf.rect.width() / xf.pw was off by the page's
height over width: Fill & Sign, form fields and Add text drew typed text
at the wrong size, and Measure snapping, Prepare form, the calculation
order and field table overlays were sized wrong too. They now use
PageXform::zoom (from #3749), which reads the side the width is on.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>