feat: node graph overlay; move to opencadcodec/opencadkernel/opencadgraph

The codec and kernel repositories and crates are renamed opencadcodec and
opencadkernel. Inside OCS they are depended on under short keys, so code
reads `codec::`, `kernel::` and the new `graph::` (opencadgraph, the node
graph engine). File-format and protocol spellings stay as they were: the
ACIS product id `acadrust`, the ACADRUST_* switches and the plugin
version keys `acadrust_version` / `acadrust_source`.

A button left of MCP on the command line opens a translucent node graph
over the viewport, with a palette of object, input, math, logic, list,
text and geometry nodes added by click or drag. An object node owns
drawing entities and its rows are the Properties panel's own rows for
them: the single-object page is extracted from refresh_properties as
entity_property_sections, values use the control protocol's
property_json, and writes go through set_property_value with a property
target override, so the panel, MCP and the graph share one read/write
path. A list reaching an object row makes one entity per element. Each
graph action is one undo step; the canvas pans and zooms.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/app/view/mod.rs

@@ -163,7 +163,7 @@ fn shortcut_key_name(key: &keyboard::Key, modifiers: keyboard::Modifiers) -> Opt
 /// `ViewportRenderMode` enum carries the raw DXF integers, not a label,
 /// so wrap it locally with a friendly name renderer.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub(super) struct RenderModeChoice(pub acadrust::entities::ViewportRenderMode);
+pub(super) struct RenderModeChoice(pub codec::entities::ViewportRenderMode);
 
 impl std::fmt::Display for RenderModeChoice {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -537,12 +537,12 @@ bg={bg_ms:.1}ms n={view_count}"
                     .flatten()
                     .and_then(|h| {
                         let indexed = match tab.scene.document.get_entity(h) {
-                            Some(acadrust::EntityType::LwPolyline(_))
-                            | Some(acadrust::EntityType::Polyline2D(_))
-                            | Some(acadrust::EntityType::Polyline3D(_))
-                            | Some(acadrust::EntityType::Spline(_))
-                            | Some(acadrust::EntityType::Face3D(_))
-                            | Some(acadrust::EntityType::PolygonMesh(_)) => true,
+                            Some(codec::EntityType::LwPolyline(_))
+                            | Some(codec::EntityType::Polyline2D(_))
+                            | Some(codec::EntityType::Polyline3D(_))
+                            | Some(codec::EntityType::Spline(_))
+                            | Some(codec::EntityType::Face3D(_))
+                            | Some(codec::EntityType::PolygonMesh(_)) => true,
                             _ => false,
                         };
                         indexed.then_some(tab.properties.prop_vertex)
@@ -612,7 +612,7 @@ bg={bg_ms:.1}ms n={view_count}"
             };
             let control_polygon = tab.selected_handle.and_then(|handle| {
                 let spline = match tab.scene.document.get_entity(handle) {
-                    Some(acadrust::EntityType::Spline(spline))
+                    Some(codec::EntityType::Spline(spline))
                         if crate::entities::spline::shows_control_vertices(spline) => spline,
                     _ => return None,
                 };
@@ -1307,7 +1307,7 @@ bg={bg_ms:.1}ms n={view_count}"
             // clicks (the shader viewport sits below it). Positioned with
             // leading Spaces sized to the viewport's screen rectangle.
             mark("active_vp_rect");
-            let active_vp_rect: Option<(acadrust::Handle, iced::Rectangle)> =
+            let active_vp_rect: Option<(codec::Handle, iced::Rectangle)> =
                 if is_paper && !tab.is_start {
                     tab.scene.active_viewport.and_then(|h| {
                         let (cw, ch) = tab.scene.selection.borrow().vp_size;
@@ -1356,7 +1356,7 @@ bg={bg_ms:.1}ms n={view_count}"
                 let vp_mode = tab
                     .scene
                     .active_viewport_render_mode()
-                    .unwrap_or(acadrust::entities::ViewportRenderMode::Wireframe2D);
+                    .unwrap_or(codec::entities::ViewportRenderMode::Wireframe2D);
                 // Adaptive (same as model): the picker measures its real width into
                 // `render_bar_w` and swaps to an empty spacer only when the viewport
                 // can't hold it; the ViewCube reads that width to decide overlap.
@@ -1828,6 +1828,11 @@ bg={bg_ms:.1}ms n={view_count}"
             }
         }
 
+        if self.show_node_graph && !tab.is_start {
+            let sections = self.graph_all_sections(self.active_tab);
+            viewport_stack = viewport_stack.push(tab.graph.view(sections));
+        }
+
         // Docked side panels (Properties, block palette, future palettes) live
         // in an ordered vertical stack on the left/right edge of the drawing
         // view. Auto-collapsing (pinned) panels that aren't being hovered
@@ -2063,6 +2068,7 @@ bg={bg_ms:.1}ms n={view_count}"
             self.control.enabled,
             self.control_busy(),
             self.pending_pick_label().is_some(),
+            self.show_node_graph,
         );
         let center_stack: Element<'_, Message> = if thumbnail_capture_clean {
             workspace