Increase ELK node spacing and revert frontend node height to 40

NODE_SPACING 40→60 gives edges more vertical room between nodes.
FIXED_H reverted to 40 to match backend NODE_HEIGHT.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/diagram/ElkDiagramRenderer.java

@@ -51,7 +51,7 @@ public class ElkDiagramRenderer implements DiagramRenderer {
     private static final int COMPOUND_TOP_PADDING = 30;
     private static final int COMPOUND_SIDE_PADDING = 10;
     private static final int CORNER_RADIUS = 8;
-    private static final double NODE_SPACING = 40.0;
+    private static final double NODE_SPACING = 60.0;
     private static final double EDGE_SPACING = 20.0;
 
     // Blue: endpoints

ui/src/pages/routes/diagram/DiagramNode.tsx

@@ -3,7 +3,7 @@ import { getNodeStyle, isCompoundType } from './nodeStyles';
 import styles from './diagram.module.css';
 
 const FIXED_W = 200;
-const FIXED_H = 52;
+const FIXED_H = 40;
 const MAX_LABEL = 22;
 
 function truncateLabel(label: string | undefined): string {