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 <[email protected]>

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),

src/scene/project.rs

@@ -507,7 +507,7 @@ impl Scene {
                 [xmin as f64, ymin as f64], [xmax as f64, ymin as f64],
                 [xmax as f64, ymax as f64], [xmin as f64, ymax as f64],
             ]];
-            if !self.images.is_empty() && !viewport.clip_boundary_handle.is_null() {
+            if !self.images.is_empty() && crate::entities::viewport::is_clipped(viewport) {
                 let boundary = self.clip_boundary_polygon(
                     viewport.clip_boundary_handle, viewport.center.z as f32);
                 if boundary.len() >= 3 {
@@ -663,7 +663,7 @@ impl Scene {
         if hw.abs() < 1e-6 || hh.abs() < 1e-6 {
             return vec![];
         }
-        let poly = if vp.clip_boundary_handle.is_null() {
+        let poly = if !crate::entities::viewport::is_clipped(vp) {
             // Rectangular viewport → its own four corners (paper coords). These
             // map to full-rect NDC [-1, 1], a no-op mask over a render target
             // that already clips to the rectangle, but it keeps rect and