fix(mleader): improve behavior and persistence

Keep annotation contexts, grip placement, and style dictionary entries consistent across editing and file saves.

Refs #779

src/app/mtext_editor.rs

@@ -1248,6 +1248,15 @@ impl super::OpenCADStudio {
                 }
                 _ => {}
             }
+            // Keep the displayed annotation context in sync.
+            if matches!(
+                self.tabs[i].scene.document.get_entity(h),
+                Some(EntityType::MultiLeader(_))
+            ) {
+                self.tabs[i]
+                    .scene
+                    .sync_displayed_annotation_context(h);
+            }
             self.tabs[i]
                 .scene
                 .bump_entities(&[(h, crate::scene::ChangeKind::Modified)]);
@@ -1336,6 +1345,14 @@ impl super::OpenCADStudio {
                 }
                 _ => {}
             }
+            if matches!(
+                self.tabs[i].scene.document.get_entity(h),
+                Some(EntityType::MultiLeader(_))
+            ) {
+                self.tabs[i]
+                    .scene
+                    .sync_displayed_annotation_context(h);
+            }
             self.tabs[i]
                 .scene
                 .bump_entities(&[(h, crate::scene::ChangeKind::Modified)]);