fix(dimension): don't draw a dimension's Defpoints markers

A dimension's definition points are baked into its *D block as POINT entities on
the Defpoints layer. AutoCAD treats them as grip markers and never draws them,
but OCS rendered them through the baked-block path as PDMODE glyphs (a vertical
tick with the drawing's PDMODE 4 / PDSIZE). Two of them sit on the measured
geometry at each extension line's foot, so the tick read as the extension line
running past the geometry — the lines looked too long.

Skip POINT sub-entities when rendering a dimension's baked block; only its lines,
arrowhead blocks and text are geometry.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/scene/convert/tess.rs

@@ -291,6 +291,15 @@ pub(crate) fn tessellate_entity(
                         let Some(sub) = document.get_entity(eh) else {
                             continue;
                         };
+                        // A dimension's definition points are baked into the
+                        // block as POINTs on the Defpoints layer. AutoCAD never
+                        // draws them as PDMODE glyphs — they're grip markers, not
+                        // geometry — so rendering them adds a stray tick at each
+                        // measured point that makes the extension lines look like
+                        // they run past the geometry. Skip them.
+                        if matches!(sub, EntityType::Point(_)) {
+                            continue;
+                        }
                         // Sub-entities inside *D### / DIMBLOCK## blocks
                         // typically use ByBlock color/linetype/lineweight —
                         // they should inherit from the Dimension entity.