perf(scene): incremental tessellation for MOVE / COPY / ERASE

Extends the Phase 2.2 per-entity memo to the common modify commands, which
still did a full bump_geometry (whole-model re-tess + block rebuild):

- transform_entities (MOVE / ROTATE / SCALE / MIRROR) marks each
  transformed handle dirty, then bump_geometry_no_blocks;
- erase_entities drops the deleted handles from the memo and
  bump_geometry_no_blocks;
- copy_entities' new handles are natural memo misses, so just
  bump_geometry_no_blocks.

All three are top-level operations (including on inserts) that can't change
a block definition, so keeping the block cache is sound. Each now
re-tessellates only the touched entities and reuses the memoized wires for
the rest, matching the grip / line-commit path.

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

src/scene/mod.rs

@@ -4711,6 +4711,7 @@ impl Scene {
             self.hatches.remove(&h);
             self.meshes.remove(&h);
             self.model_solids.remove(&h);
+            self.mark_entity_dirty(h);
         }
         // Remove erased handles from all groups; delete groups that become empty.
         let group_dict_handle = self.document.header.acad_group_dict_handle;
@@ -4738,7 +4739,9 @@ impl Scene {
             }
             self.document.objects.remove(gh);
         }
-        self.bump_geometry();
+        // Deleting top-level entities/inserts leaves block definitions intact;
+        // the erased handles were already dropped from the memo above.
+        self.bump_geometry_no_blocks();
     }
 
     // ── Group helpers ──────────────────────────────────────────────────────
@@ -4908,7 +4911,13 @@ impl Scene {
                 }
             }
         }
-        self.bump_geometry();
+        // Only the transformed entities changed (a top-level move/rotate/scale/
+        // mirror never edits a block definition) — re-tessellate just those and
+        // keep the block cache + every other entity's memoized wires.
+        for &h in handles {
+            self.mark_entity_dirty(h);
+        }
+        self.bump_geometry_no_blocks();
     }
 
     pub fn copy_entities(&mut self, handles: &[Handle], t: &EntityTransform) -> Vec<Handle> {
@@ -4939,7 +4948,9 @@ impl Scene {
             }
             new_handles.push(h);
         }
-        self.bump_geometry();
+        // The copies are new handles (natural memo misses, tessellated fresh)
+        // and reference only already-cached blocks — no block defn changes.
+        self.bump_geometry_no_blocks();
         new_handles
     }