Dimension tool: Expand keeps a dimension as plain art after it moves

Object > Expand left a dimension's recipe on its group, so the next move
redrew the live dimension and discarded the expanded art. Expand now ends
the live link of a dimension whose art it changes, in the same undo step.
Moving or scaling the group leaves its art as it is, the art no longer
follows what it measured, and undo gives the live dimension back.

Expand Appearance, Create Outlines and Outline Stroke had the same fault
and now do the same, also when they reach only a part of a dimension. A
dimension whose art a command leaves as it was stays live. A dimension
selected with the art it measures becomes a plain group when Expand,
Expand Appearance or Outline Stroke replaces only that art.

crates/engine/src/cmd/pathops.rs

@@ -134,7 +134,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Outline Stroke",
             ["Object", "Path"],
             None,
-            "{} replace stroked paths with filled outlines → {ids}",
+            "{} replace stroked paths with filled outlines; a dimension whose lines are outlined, or selected with the art it measures when that art is outlined, becomes a plain group of its art → {ids}",
             has_selection,
             outline_stroke
         ),
@@ -980,6 +980,8 @@ pub(crate) fn replace_leaves(d: &mut Document, root: NodeId, mut f: impl FnMut(&
 fn outline_stroke(s: &mut Session, _: &Value) -> Result<Value> {
     let roots = selected_roots(s)?;
     let ids = s.edit("Outline Stroke", |d, sel| {
+        let before = d.clone();
+        let mut ended = super::dimension::end_links(d, &roots);
         let brushes = vectorcraft_brush::library(d);
         let mut new_sel = vec![];
         let mut changed = 0;
@@ -988,6 +990,9 @@ fn outline_stroke(s: &mut Session, _: &Value) -> Result<Value> {
             new_sel.push(id);
             changed += n;
         }
+        // A dimension whose source was outlined stays plain: its link no longer fits that art.
+        ended.retain(|e| e.source_kept(&before, d));
+        super::dimension::restore_unchanged(d, ended);
         if changed == 0 {
             return Err(EngineError::Other("Outline Stroke: no stroked paths selected".into()));
         }