Track subcall read regions within read-only calls

crates/objects/src/store.rs

@@ -21,6 +21,16 @@ impl ObjectStore {
     pub fn end_read_only(&mut self, scope: usize) -> Result<Vec<ObjectRef>, VmError> {
         self.heap.end_read_only(scope)
     }
+    /// Track one subcall inside the active read-only scope. Regions nest in
+    /// LIFO order and do not clear the enclosing call's read dependencies.
+    /// Handles returned by end_read_tracking are borrowed, never owning roots.
+    pub fn begin_read_tracking(&self) -> Result<usize, VmError> {
+        self.heap.begin_read_tracking()
+    }
+    pub fn end_read_tracking(&self, token: usize) -> Result<Vec<ObjectRef>, VmError> {
+        self.heap.end_read_tracking(token)
+    }
+
     pub fn is_read_only(&self) -> bool {
         self.heap.is_read_only()
     }