fix(scene): hatch pattern scale and per-entity annotative check

- Hatch pattern_scale multiplied by annotation_scale in model space so
  pattern density stays consistent when CANNOSCALE changes
- Annotative check now uses AcAnnoPO xdata (R2007+ marker) instead of
  relying solely on group-code-293 flag; falls back to is_annotative
  for files with no xdata (old DXF backward compat)
- acadrust patched to local path for is_annotative field

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/scene/mod.rs

@@ -1573,7 +1573,8 @@ impl Scene {
                     match &mut m.pattern {
                         hatch_model::HatchPattern::Pattern(_) => {
                             m.angle_offset = dxf.pattern_angle as f32;
-                            m.scale = dxf.pattern_scale as f32;
+                            let anno = if self.current_layout == "Model" { self.annotation_scale } else { 1.0 };
+                            m.scale = dxf.pattern_scale as f32 * anno;
                         }
                         hatch_model::HatchPattern::Gradient { angle_deg, .. } => {
                             *angle_deg = dxf.pattern_angle.to_degrees() as f32;