refactor(tess): rename LegacyTess → FallbackTess

The trait isn't deprecating anything — it carries the path entities
take when they're not covered by the truck topology pipeline
(Viewport, Insert, Hatch outline, Ole2Frame). "Fallback" names the
purpose; "Legacy" implied retirement that isn't actually on the
roadmap.

Same rename for LegacyGeometry → FallbackGeometry,
legacy_geometry() → fallback_geometry().

Co-Authored-By: Claude Opus 4.7 <[email protected]>

src/entities/hatch.rs

@@ -3,9 +3,9 @@ use glam::Vec3;
 
 use crate::command::EntityTransform;
 use crate::entities::common::{diamond_grip, edit_prop as edit, parse_f64, ro_prop as ro};
-use crate::entities::traits::{Grippable, LegacyTess, PropertyEditable, Transformable};
+use crate::entities::traits::{Grippable, FallbackTess, PropertyEditable, Transformable};
 use crate::scene::object::{GripApply, GripDef, PropSection, PropValue, Property};
-use crate::scene::tess_util::{arc_segments, arc_signed_span, wire_chord_tol, LegacyGeometry};
+use crate::scene::tess_util::{arc_segments, arc_signed_span, wire_chord_tol, FallbackGeometry};
 use crate::scene::wire_model::SnapHint;
 
 fn properties(h: &Hatch) -> PropSection {
@@ -350,8 +350,8 @@ impl Grippable for Hatch {
     }
 }
 
-impl LegacyTess for Hatch {
-    fn legacy_geometry(&self, world_offset: [f64; 3]) -> LegacyGeometry {
+impl FallbackTess for Hatch {
+    fn fallback_geometry(&self, world_offset: [f64; 3]) -> FallbackGeometry {
         let [ox, oy, oz] = world_offset;
         let normal = (self.normal.x, self.normal.y, self.normal.z);
         // Convert a 2D OCS hatch boundary point to WCS, then subtract world_offset.

src/entities/insert.rs

@@ -119,8 +119,8 @@ impl Transformable for Insert {
     }
 }
 
-impl crate::entities::traits::LegacyTess for Insert {
-    fn legacy_geometry(&self, world_offset: [f64; 3]) -> crate::scene::tess_util::LegacyGeometry {
+impl crate::entities::traits::FallbackTess for Insert {
+    fn fallback_geometry(&self, world_offset: [f64; 3]) -> crate::scene::tess_util::FallbackGeometry {
         let [ox, oy, oz] = world_offset;
         let ip = Vec3::new(
             (self.insert_point.x - ox) as f32,

src/entities/ole2frame.rs

@@ -202,8 +202,8 @@ impl Transformable for Ole2Frame {
     }
 }
 
-impl crate::entities::traits::LegacyTess for Ole2Frame {
-    fn legacy_geometry(&self, world_offset: [f64; 3]) -> crate::scene::tess_util::LegacyGeometry {
+impl crate::entities::traits::FallbackTess for Ole2Frame {
+    fn fallback_geometry(&self, world_offset: [f64; 3]) -> crate::scene::tess_util::FallbackGeometry {
         // OLE objects carry a bounding rectangle in model space.
         // Render a simple X-through-rectangle placeholder.
         let [ox, oy, oz] = world_offset;

src/entities/traits.rs

@@ -3,18 +3,18 @@ use acadrust::{CadDocument, EntityType};
 use crate::command::EntityTransform;
 use crate::scene::acad_to_truck::TruckEntity;
 use crate::scene::object::{GripApply, GripDef, PropSection};
-use crate::scene::tess_util::LegacyGeometry;
+use crate::scene::tess_util::FallbackGeometry;
 
 pub trait TruckConvertible {
     fn to_truck(&self, document: &CadDocument) -> Option<TruckEntity>;
 }
 
-/// Legacy fallback geometry for entities not covered by the truck
-/// topology pipeline (Viewport, Insert, Hatch outline, Ole2Frame, …).
-/// Returns world-offset-relative `f32` points + snap/key vertices the
+/// Fallback geometry for entities not routed through the truck topology
+/// pipeline (Viewport, Insert, Hatch outline, Ole2Frame). Returns
+/// world-offset-relative `f32` points + snap/key vertices the
 /// dispatcher wraps into a `WireModel`.
-pub trait LegacyTess {
-    fn legacy_geometry(&self, world_offset: [f64; 3]) -> LegacyGeometry;
+pub trait FallbackTess {
+    fn fallback_geometry(&self, world_offset: [f64; 3]) -> FallbackGeometry;
 }
 
 pub trait Grippable {

src/entities/viewport.rs

@@ -567,8 +567,8 @@ impl Transformable for Viewport {
     }
 }
 
-impl crate::entities::traits::LegacyTess for Viewport {
-    fn legacy_geometry(&self, world_offset: [f64; 3]) -> crate::scene::tess_util::LegacyGeometry {
+impl crate::entities::traits::FallbackTess for Viewport {
+    fn fallback_geometry(&self, world_offset: [f64; 3]) -> crate::scene::tess_util::FallbackGeometry {
         let [ox, oy, oz] = world_offset;
         let cx = (self.center.x - ox) as f32;
         let cy = (self.center.y - oy) as f32;