Cargo: codec aad7053, kernel 1a52eaf, graph 263de59; honour viewport clipping

Brings codec PRs #84 (cross-version visual styles, table styles,
subentity managers), #88 (viewport clipping flag, DXF boundary handle),
#89 (DXF viewport snap/twist in degrees) and #92 (field format codes,
event updates).

With #88 a viewport keeps a stored boundary whether or not clipping is
on, so a linked boundary alone no longer means "clipped": rendering,
paper picking, VPCLIP and the Clipped property check the clipping flag
too, and VPCLIP / MVIEW Object and Polygon set it. Before, OCS never set
the flag, so its clipped viewports opened rectangular elsewhere.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scene/mspace.rs

@@ -189,7 +189,7 @@ impl Scene {
         if (paper.x - vp.center.x).abs() > hw || (paper.y - vp.center.y).abs() > hh {
             return false;
         }
-        if vp.clip_boundary_handle.is_null() {
+        if !crate::entities::viewport::is_clipped(vp) {
             return true;
         }
         let Some(boundary) = self.document.get_entity(vp.clip_boundary_handle)
@@ -321,6 +321,7 @@ mod clip_tests {
         viewport.width = 20.0;
         viewport.height = 20.0;
         viewport.clip_boundary_handle = clip;
+        viewport.status.non_rectangular_clipping = true;
         let viewport = scene.add_entity(EntityType::Viewport(viewport));
         for (x, y, inside) in [
             (2.0, 2.0, true), (8.0, 2.0, true), (8.0, 8.0, false),