fix: expose and apply control marking handles

workbench/client/src/App.tsx

@@ -204,8 +204,15 @@ function App() {
   }, []);
   /** A drag becomes one drafted constraint layered over the session's document. */
   const draftFor = (handle: EditHandle, value: number): PreviewDraft | null => {
+    // Road-anchored edits carry a directional road id. Junction-approach
+    // controls are keyed by segment instead, so resolve them through the
+    // compiled model before building the anchor snapshot. Without this branch
+    // control handles silently returned null and never scheduled a preview.
     const roadId = 'roadId' in handle.anchor ? handle.anchor.roadId : null;
-    const road = roadId ? state?.compiled.model.roads.find((item) => item.id === roadId) : undefined;
+    const segmentId = 'segmentId' in handle.anchor ? handle.anchor.segmentId : null;
+    const road = state?.compiled.model.roads.find(
+      (item) => (roadId ? item.id === roadId : false) || (segmentId ? item.segmentId === segmentId : false),
+    );
     // Without a centerline there is no snapshot to record, so drop the drag rather
     // than send a constraint the server would have to reject.
     if (!session || !road || road.centerline.length < 2) return null;