pdfcraft-model

Layer L2: typed views over the pdfcraft-cos object graph. It starts small, with what several L3/L4 crates need:

pages(doc): leaf pages in order, each with its inherited attributes (Resources, MediaBox, CropBox, Rotate, §7.7.3.4) resolved;
Page::crop, Page::rotation, Page::user_unit and Page::view_matrix: the displayed page's geometry, and the matrix from "display space" (points, origin at the bottom-left of the page as shown, after /UserUnit and /Rotate) to user space, so content can be placed the way the reader sees the page. /UserUnit is read as Acrobat reads it: the page's own entry, a number from 1 up, at most 75,000; anything else counts as 1. view_matrix_for(rotation, rect) is the same matrix for any rectangle, e.g. to draw a comment's picture upright inside its user-space /Rect on a turned page.

organize, annot and forms still carry their own small walkers; they move here as the model grows (ADR-0004).