feat(statusbar): highlight cycling-list object on row hover

Add a scene hover_highlight handle that renders an entity with the
selection colour without joining the real selection. The cycling list
box sets it on row enter / clears on exit, so hovering a row glows the
matching object in the drawing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/update.rs

@@ -3631,19 +3631,27 @@ impl OpenCADStudio {
             Message::ToggleSelectionCycling => {
                 self.selection_cycling ^= true;
                 self.cycle_candidates = None;
+                self.tabs[self.active_tab].scene.set_hover_highlight(None);
                 Task::none()
             }
             Message::CycleSelect(handle) => {
                 // Add the picked object to the current selection (accumulate).
                 self.cycle_candidates = None;
                 let i = self.active_tab;
+                self.tabs[i].scene.set_hover_highlight(None);
                 self.tabs[i].scene.select_entity(handle, false);
                 self.tabs[i].scene.expand_selection_for_groups(&[handle]);
                 self.refresh_properties();
                 Task::none()
             }
+            Message::CycleHover(handle) => {
+                let i = self.active_tab;
+                self.tabs[i].scene.set_hover_highlight(handle);
+                Task::none()
+            }
             Message::CycleCancel => {
                 self.cycle_candidates = None;
+                self.tabs[self.active_tab].scene.set_hover_highlight(None);
                 Task::none()
             }
             Message::ToggleSelectionFilterPopup => {