fix(geometry): honor polyline OCS in commands

Route editing and derived geometry through kernel world-space curves.\n\nRefs #797\nRefs #798\nRefs #799

src/modules/draw/modify/offset.rs

@@ -10,7 +10,7 @@
 //     3. Pick a point on the side to offset toward, or choose Multiple
 //        to keep offsetting the newly created result at the same distance
 
-use crate::entities::curve::entity_curve;
+use crate::entities::curve::{entity_curve, lwpolyline_world_xy};
 use crate::modules::draw::modify::spline_ops::spline_sample_xy;
 use acadrust::entities::LwVertex;
 use acadrust::entities::{
@@ -160,6 +160,9 @@ fn offset_arc(a: &ArcEnt, dist: f64, side_pt: Vec3) -> Option<EntityType> {
 /// offset passed to the algorithm is always ±1. This avoids fixed-epsilon
 /// failures on tiny drawings and on UTM-scale coordinates.
 fn offset_lwpolylines(p: &LwPolyline, dist: f64, side_pt: Vec3) -> Vec<EntityType> {
+    let Some(p) = lwpolyline_world_xy(p) else {
+        return Vec::new();
+    };
     let source = KernelPolyline {
         closed: p.is_closed,
         vertices: p