debug: v2 ELK logging to verify handler separation in new build

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

@@ -278,6 +278,17 @@ public class ElkDiagramRenderer implements DiagramRenderer {
             engine.layout(handlerRoot, new BasicProgressMonitor());
         }
 
+        // Debug: log root dimensions and children after layout
+        System.out.println("[ELK-v2] rootNode " + rootNode.getWidth() + "x" + rootNode.getHeight()
+                + " children=" + rootNode.getChildren().size()
+                + " mainNodes=" + mainNodes.size() + " handlerNodes=" + handlerNodes.size());
+        for (ElkNode child : rootNode.getChildren()) {
+            System.out.println("[ELK-v2]   " + child.getIdentifier()
+                    + " x=" + String.format("%.1f", child.getX())
+                    + " y=" + String.format("%.1f", child.getY())
+                    + " parent=" + (child.getParent() != null ? child.getParent().getIdentifier() : "null"));
+        }
+
         // Extract positioned nodes
         List<PositionedNode> positionedNodes = new ArrayList<>();
         Map<String, CompoundInfo> compoundInfos = new HashMap<>();