fix: align main flow at DO_TRY top and stretch sections to full width

Port alignment BEGIN on DO_TRY compounds makes edges attach at the top
instead of center, keeping the main flow level. Post-processing also
stretches all DO_TRY sections (doFinally, doCatch) to match the widest
section's width for visual consistency.

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

@@ -334,6 +334,7 @@ public class ElkDiagramRenderer implements DiagramRenderer {
         }
 
         // Post-process DO_TRY compounds: re-stack sections in correct order
+        // and stretch all sections to the same width
         // (ELK doesn't reliably order disconnected children within a compound)
         for (Map.Entry<String, List<String>> entry : doTrySectionOrder.entrySet()) {
             List<String> orderedIds = entry.getValue();
@@ -344,6 +345,7 @@ public class ElkDiagramRenderer implements DiagramRenderer {
             }
             if (sections.size() < 2) continue;
 
+            // Re-stack in correct vertical order
             double startY = sections.stream().mapToDouble(ElkNode::getY).min().orElse(0);
             double spacing = NODE_SPACING * 0.4; // matches DO_TRY spacing
             double currentY = startY;
@@ -351,6 +353,12 @@ public class ElkDiagramRenderer implements DiagramRenderer {
                 section.setY(currentY);
                 currentY += section.getHeight() + spacing;
             }
+
+            // Stretch all sections to the widest one's width
+            double maxWidth = sections.stream().mapToDouble(ElkNode::getWidth).max().orElse(0);
+            for (ElkNode section : sections) {
+                section.setWidth(maxWidth);
+            }
         }
 
         // Extract positioned nodes
@@ -577,6 +585,9 @@ 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<>();