Bound Process payload sizes and capture rendered order feedback

Box the optional Process menu context and changed order command without changing identity or command semantics. Add opt-in actual WGPU readbacks to the split-event OA/SA reorder evaluator. Strict all-target lint, format and affected desktop paths pass; native acceptance follows.

crates/oa-desktop/src/behavior/topology/direct_selection.rs

@@ -245,7 +245,7 @@ impl Graph<'_> {
             };
             let mut request = crate::model_menu::Request::object(object, pointer);
             request.selection_target = Some(Box::new(target));
-            request.process = Some(context);
+            request.process = Some(Box::new(context));
             return Some(
                 Action::publish(Message::Menu(crate::model_menu::Event::Open(request)))
                     .and_capture(),

crates/oa-desktop/src/behavior/topology/direct_selection_tests.rs

@@ -127,14 +127,16 @@ fn group_drag_uses_midpoint_anchors_and_original_order_and_singleton_after_gap()
             };
             assert_eq!(snapshot, graph.selection.clone().unwrap());
             assert_eq!(destination, Destination::After(f.nodes[1]));
-            let Plan::Change(Command::SetSteps(owner, steps)) =
-                Prepared::new(&f.p, f.owner, snapshot.targets())
-                    .unwrap()
-                    .plan(destination)
-                    .unwrap()
+            let Plan::Change(command) = Prepared::new(&f.p, f.owner, snapshot.targets())
+                .unwrap()
+                .plan(destination)
+                .unwrap()
             else {
                 panic!("changed steps");
             };
+            let Command::SetSteps(owner, steps) = *command else {
+                panic!("expected SetSteps");
+            };
             assert_eq!(owner, f.owner);
             assert_eq!(steps, vec![f.nodes[1], f.nodes[0], f.nodes[2]]);
         }
@@ -302,7 +304,7 @@ fn qualified_occurrences_and_visible_preview_links_keep_exact_invocation_paths()
             matches!(press(&graph, &mut input, at), Some(Message::DiagramSelection(SelectionEvent::Choose(_, target, Choice::Toggle))) if target == expected)
         );
         assert!(
-            matches!(send(&graph, &mut input, canvas::Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Right)), at), Some(Message::Menu(crate::model_menu::Event::Open(request))) if request.selection_target.as_deref() == Some(&expected) && request.process == graph.interaction.map(|(context,_,_)| context))
+            matches!(send(&graph, &mut input, canvas::Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Right)), at), Some(Message::Menu(crate::model_menu::Event::Open(request))) if request.selection_target.as_deref() == Some(&expected) && request.process.as_deref().copied() == graph.interaction.map(|(context,_,_)| context))
         );
     }
     assert_ne!(targets[0], targets[1]);

crates/oa-desktop/src/behavior/topology/direct_tests.rs

@@ -365,7 +365,7 @@ fn direct_process_reconnect_delete_and_reorder_preserve_other_paths_and_sources(
     else {
         panic!("changed order");
     };
-    let reordered = execute_batch(&f.p, &[command]).unwrap();
+    let reordered = execute_batch(&f.p, &[*command]).unwrap();
     assert_eq!(reordered.elements[&f.owner].steps().unwrap()[0], f.nodes[2]);
     assert_eq!(reordered.relations, f.p.relations);
     assert!(direct::reorder(&f.p, f.owner, f.nodes[0], f.nodes[1]).is_err());

crates/oa-desktop/src/behavior/topology/group_reorder.rs

@@ -11,7 +11,7 @@ pub(crate) enum Destination {
 #[derive(Debug)]
 pub(crate) enum Plan {
     Noop,
-    Change(Command),
+    Change(Box<Command>),
 }
 
 /// Captured semantic facts only: no project clone, projection or routed scene.
@@ -156,7 +156,9 @@ impl Prepared {
                 "This reorder would change process columns; the whole move was refused.".into(),
             );
         }
-        Ok(Plan::Change(Command::SetSteps(self.owner, ordered)))
+        Ok(Plan::Change(Box::new(Command::SetSteps(
+            self.owner, ordered,
+        ))))
     }
 }
 

crates/oa-desktop/src/behavior/topology/group_reorder/tests.rs

@@ -56,8 +56,8 @@ fn changed(project: &Project, owner: Id, targets: &[Target], drop: Destination)
     let Plan::Change(command) = plan(project, owner, targets, drop).unwrap() else {
         panic!("Expected an actual order change");
     };
-    assert!(matches!(&command, Command::SetSteps(id, _) if *id == owner));
-    command
+    assert!(matches!(command.as_ref(), Command::SetSteps(id, _) if *id == owner));
+    *command
 }
 
 #[test]
@@ -395,7 +395,7 @@ fn process_group_columns_parallel_links_keep_exact_ranks_and_relation_records()
         let Plan::Change(command) = prepared.plan(Destination::Before(a)).unwrap() else {
             panic!("Expected move");
         };
-        let result = execute_batch(&project, &[command]).unwrap();
+        let result = execute_batch(&project, &[*command]).unwrap();
         assert_eq!(
             result.elements[&owner].steps().unwrap(),
             &vec![b, u, c, v, a]

crates/oa-desktop/src/behavior/topology/layout_tests.rs

@@ -192,6 +192,47 @@ async fn production_process_multiselect_reverse_click_group_drop_has_one_history
         let snapshot = app.multiselect_snapshot().unwrap();
         let source = app.document.bundle().clone();
         let camera = (app.behavior.topology.pan, app.behavior.topology.zoom);
+        // Reuse the existing opt-in raw WGPU evidence convention. These are
+        // actual production-tree pixels, not a reconstructed preview image.
+        let record_feedback = |stage: &str, mounted: &mut Mounted, app: &App, cursor: Point| {
+            let Some(path) = std::env::var_os("ARCADIA_RENDER_EVIDENCE_DIR") else {
+                return;
+            };
+            let path = std::path::PathBuf::from(path);
+            std::fs::create_dir_all(&path).unwrap();
+            let name = format!("process-{layer:?}-{stage}");
+            let pixels = mounted.pixels_at(app, mouse::Cursor::Available(cursor));
+            let width = app.window_size.width as u32;
+            let height = app.window_size.height as u32;
+            assert_eq!(pixels.len(), width as usize * height as usize * 4);
+            let mut file = std::fs::OpenOptions::new()
+                .write(true)
+                .create_new(true)
+                .open(path.join(format!("{name}.rgba")))
+                .unwrap();
+            std::io::Write::write_all(&mut file, &pixels).unwrap();
+            let metadata = serde_json::json!({
+                "width": width, "height": height, "format": "RGBA8",
+                "stage": stage, "layer": format!("{layer:?}"),
+                "canvas": [bounds.x, bounds.y, bounds.width, bounds.height],
+                "cursor": [cursor.x, cursor.y], "scale": scale,
+                "camera": [app.behavior.topology.pan.x, app.behavior.topology.pan.y],
+                "selectionCount": snapshot.targets().len(),
+                "selection": format!("{snapshot:?}"),
+                "source": app.document.bundle(),
+            });
+            let mut file = std::fs::OpenOptions::new()
+                .write(true)
+                .create_new(true)
+                .open(path.join(format!("{name}.json")))
+                .unwrap();
+            std::io::Write::write_all(&mut file, &serde_json::to_vec_pretty(&metadata).unwrap())
+                .unwrap();
+            assert_eq!(app.document.bundle(), &source);
+            assert_eq!(app.multiselect_snapshot().unwrap(), snapshot);
+            assert!(!app.document.can_undo());
+        };
+        record_feedback("before-press", &mut mounted, &app, points[1]);
         let pressed = mounted
             .batch(
                 &mut app,
@@ -235,6 +276,7 @@ async fn production_process_multiselect_reverse_click_group_drop_has_one_history
             (app.behavior.topology.pan, app.behavior.topology.zoom),
             camera
         );
+        record_feedback("after-motion", &mut mounted, &app, points[2]);
         let messages = mounted
             .batch(
                 &mut app,