fix: review fixes for the Aligned 2Lines placement and DCCONVERT

The 2Lines placement (#1459) wrote the second line's new ends back with
`set_resolved_point`, which was not the inverse of the `resolve_point` it
paired with. `resolve_point` reads polyline vertices in WCS through the
polyline's OCS; the writer put that world point straight into the OCS
vertex, so a mirrored polyline (normal -Z, common in real drawings) had
its vertex flipped, and the closing segment's end marker — which names
vertex 0 on a closed polyline — found no vertex and the placement was
silently dropped. The writer now converts back into the OCS, keeps the
polyline's own elevation, and wraps the closing marker the same way.

The same arm pushed `test_pline_line_then_arc` past the default test
thread's stack: its locals, a cloned entity among them, sat in the frame
of the command-result dispatcher, which is on the stack of every click.
The placement is built out of line and handed over boxed.

Merging #1447 had left nothing setting DIMCONSTRAINT's default to
Diameter; the Dispatch arm #1461 turned into a match now covers it with
Radius and Convert. DCCONVERT's result lines go through the translation
macros.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/command_driver.rs

@@ -4794,7 +4794,7 @@ impl OpenCADStudio {
                 second_ends,
             } => {
                 use crate::scene::parametric_constraints::{
-                    resolve_point, set_resolved_point, two_lines_placement, ConstraintKind,
+                    resolve_point, two_lines_placed_entity, ConstraintKind,
                 };
                 let scope = self.tabs[i].current_parametric_scope();
                 let refs = [first_line, second_line];
@@ -4806,38 +4806,16 @@ impl OpenCADStudio {
                     return self.apply_cmd_result(CmdResult::ReportError(message.to_string()));
                 }
                 // The reference's placement of the second line, written
-                // before the Parallel constraint holds it there.
-                let placed = {
-                    let document = &self.tabs[i].scene.document;
-                    let world = |reference: crate::scene::parametric_constraints::ParametricRef| {
-                        let entity = document.get_entity(reference.entity)?;
-                        let point = resolve_point(entity, reference.marker?)?;
-                        Some(glam::DVec3::new(point.x, point.y, point.z))
-                    };
-                    let ends = |pair: [crate::scene::parametric_constraints::ParametricRef; 2]| {
-                        Some([world(pair[0])?, world(pair[1])?])
-                    };
-                    ends(first_ends)
-                        .zip(ends(second_ends))
-                        .and_then(|(first, second)| two_lines_placement(first, first_pick, second))
-                };
-                let placed_entity = placed.and_then(|points| {
-                    let mut entity = self.tabs[i]
-                        .scene
-                        .document
-                        .get_entity(second_line.entity)
-                        .cloned()?;
-                    let written = second_ends.iter().zip(points).all(|(reference, point)| {
-                        reference.marker.is_some_and(|marker| {
-                            set_resolved_point(
-                                &mut entity,
-                                marker,
-                                acadrust::types::Vector3::new(point.x, point.y, point.z),
-                            )
-                        })
-                    });
-                    written.then_some(entity)
-                });
+                // before the Parallel constraint holds it there. Built out of
+                // line and boxed: this arm's locals would otherwise sit in
+                // `apply_cmd_result`'s frame, which is on every click's stack.
+                let placed_entity = two_lines_placed_entity(
+                    &self.tabs[i].scene.document,
+                    first_ends,
+                    first_pick,
+                    second_line,
+                    second_ends,
+                );
                 let already = self.tabs[i]
                     .scene
                     .parametric_constraint_set(scope)
@@ -4861,11 +4839,7 @@ impl OpenCADStudio {
                         });
                     let pending = self.begin_undo(i, "Parallel constraint", 1, true);
                     if let Some(entity) = placed_entity {
-                        let before = self.tabs[i].scene.document.get_entity_arc(second_line.entity);
-                        self.tabs[i]
-                            .scene
-                            .record_undo_before(second_line.entity, before);
-                        self.tabs[i].scene.update_entity(entity);
+                        self.tabs[i].scene.replace_entity_recorded(entity);
                     }
                     self.tabs[i]
                         .scene
@@ -6286,6 +6260,7 @@ impl OpenCADStudio {
                 if from_menu {
                     match cmd.as_str() {
                         "DCRADIUS" => self.dim_constraint_last = "Radius",
+                        "DCDIAMETER" => self.dim_constraint_last = "Diameter",
                         "DCCONVERT" => self.dim_constraint_last = "Convert",
                         _ => {}
                     }