feat: Solid3D (3DSOLID) ACIS tessellation

Parse SAT geometry directly into GPU MeshModel without going through
the truck B-rep pipeline:
  • plane-surface faces  → fan-triangulate the coedge-loop polygon
  • cone-surface faces   → parametric grid (handles cylinders and cones)
  • sphere-surface faces → UV sphere grid (GRID_U × GRID_V)
  • torus-surface faces  → UV torus grid

Scene integration:
  • add_entity(): tessellates Solid3D on insert, stores in scene.meshes
  • erase_entities(): removes mesh from scene.meshes on delete
  • populate_meshes_from_document(): rebuilds all meshes on file load
    and undo/redo (called alongside populate_hatches/images)

ROADMAP updated: Solid3D tessellation marked ✅ in sections 2.12, 14.

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

src/app/history.rs

@@ -36,8 +36,8 @@ impl H7CAD {
             .collect::<HashSet<_>>();
         self.tabs[i].scene.populate_hatches_from_document();
         self.tabs[i].scene.populate_images_from_document();
+        self.tabs[i].scene.populate_meshes_from_document();
         self.tabs[i].scene.clear_preview_wire();
-        self.tabs[i].scene.meshes.clear();
         self.tabs[i].scene.images.clear();
         self.tabs[i].active_cmd = None;
         self.tabs[i].snap_result = None;

src/app/update.rs

@@ -50,6 +50,7 @@ impl H7CAD {
                 self.tabs[i].scene.document = doc;
                 self.tabs[i].scene.populate_hatches_from_document();
                 self.tabs[i].scene.populate_images_from_document();
+                self.tabs[i].scene.populate_meshes_from_document();
                 self.tabs[i].scene.selected = std::collections::HashSet::new();
                 self.tabs[i].scene.preview_wires = vec![];
                 self.tabs[i].scene.current_layout = "Model".to_string();