Fix #3233: an opened dimension whose label characters are off the colour mode is redrawn too

Review follow-up (CodeRabbit): a text node's characters carry their own fill
(CharStyle), saved apart from the node's appearance, so conform also checks
the runs of the label. dimension_colours_follow_the_document_colour_model
opens a CMYK document whose label characters alone are RGB; without the
change they stay RGB.

crates/engine/src/cmd/dimension.rs

@@ -254,7 +254,13 @@ pub(crate) fn conform(doc: &mut Document) {
     doc.walk(|n| {
         if let Some(d) = &n.extras().dimension {
             let mut off = false;
-            n.walk(&mut |c| off |= [c.appearance.fill_paint(), c.appearance.stroke_paint()].iter().filter_map(|p| p.color()).any(|c| off_mode(&c)));
+            n.walk(&mut |c| {
+                off |= [c.appearance.fill_paint(), c.appearance.stroke_paint()].iter().filter_map(|p| p.color()).any(|c| off_mode(&c));
+                // The label's characters carry their own fill.
+                if let NodeKind::Text(t) = &c.kind {
+                    off |= t.runs.iter().filter_map(|r| r.style.fill.color()).any(|c| off_mode(&c));
+                }
+            });
             if off {
                 stale.push((n.id, (**d).clone()));
             }

crates/engine/tests/dimensions.rs

@@ -520,4 +520,26 @@ fn dimension_colours_follow_the_document_colour_model() {
     s.add_document(old, None);
     let opened = colours(&s, id);
     assert!(!opened.is_empty() && opened.iter().all(|c| *c == k), "{opened:?}");
+    // Only the label's characters in RGB (their fill is saved apart from the node's): redrawn too.
+    let mut old = (*s.doc().unwrap().doc).clone();
+    let label = {
+        let mut found = None;
+        old.node(NodeId(id)).unwrap().walk(&mut |n| {
+            if matches!(n.kind, vectorcraft_doc::NodeKind::Text(_)) {
+                found = Some(n.id);
+            }
+        });
+        found.expect("a dimension label")
+    };
+    if let Some(vectorcraft_doc::NodeKind::Text(t)) = old.node_mut(label).map(|n| &mut n.kind) {
+        for r in &mut t.runs {
+            r.style.fill = vectorcraft_color::Paint::solid(vectorcraft_color::Color::rgb8(0, 0, 0));
+        }
+    }
+    s.add_document(old, None);
+    let runs = |s: &Session| match &s.doc().unwrap().doc.node(label).unwrap().kind {
+        vectorcraft_doc::NodeKind::Text(t) => t.runs.iter().filter_map(|r| r.style.fill.color()).collect::<Vec<_>>(),
+        _ => Vec::new(),
+    };
+    assert!(!runs(&s).is_empty() && runs(&s).iter().all(|c| *c == k), "{:?}", runs(&s));
 }