Fix findUsages/undo/node-lookup bugs, split Viewport and Editor, share command and inspector helpers

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/editor/graph/NodeView.ts

@@ -6,7 +6,11 @@ import type { PropertyDef } from '../../core/properties/PropertySchema';
 import { Theme, textStyle, type TextStyleToken, Widget } from '../../ui';
 import { keyLabel } from '../inspector/fieldFactory';
 
-/** Node geometry in graph units; the editor relies on it for edge anchors and hit tests. */
+/**
+ * Node geometry in graph units – what the node lays itself out, draws and hit-tests with.
+ * Exported as the single source of these numbers: edge anchors have to land exactly on the
+ * ports drawn here.
+ */
 export const NODE_WIDTH = 176;
 export const TITLE_HEIGHT = 24;
 export const ROW_HEIGHT = 20;