fix: vertically center DO_TRY block relative to outer flow nodes

Remove PORT_ALIGNMENT_DEFAULT=BEGIN so NETWORK_SIMPLEX centers edges
at the vertical midpoint of the compound instead of the top.

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

@@ -562,10 +562,6 @@ public class ElkDiagramRenderer implements DiagramRenderer {
             elkNode.setProperty(CoreOptions.PADDING,
                     new org.eclipse.elk.core.math.ElkPadding(COMPOUND_TOP_PADDING,
                             COMPOUND_SIDE_PADDING, COMPOUND_SIDE_PADDING, COMPOUND_SIDE_PADDING));
-            // Attach edges at the top of the compound so the main flow stays level
-            elkNode.setProperty(CoreOptions.PORT_ALIGNMENT_DEFAULT,
-                    org.eclipse.elk.core.options.PortAlignment.BEGIN);
-
             // Separate try body children from handler children
             List<RouteNode> tryBodyChildren = new ArrayList<>();
             List<RouteNode> handlerChildren = new ArrayList<>();