Exclude corridor-rerouted edges from EndSink highway grouping

Edges with bend points above the graph (Y < graphMinY - 10) are
corridor-rerouted and should render independently, not merge into
a shared End-targeting highway. The highway truncation was destroying
the corridor route paths, making edges appear to end before the node.

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

src/Workflow/__Libraries/StellaOps.Workflow.Renderer.Svg/WorkflowRenderSvgRenderer.cs

@@ -1507,6 +1507,8 @@ public sealed class WorkflowRenderSvgRenderer
         var groups = new Dictionary<string, EndSinkGroup>(StringComparer.Ordinal);
         var nodesById = layout.Nodes.ToDictionary(node => node.Id, StringComparer.Ordinal);
 
+        var graphMinY = layout.Nodes.Min(node => node.Y);
+
         foreach (var group in layout.Edges
                      .Where(edge => edge.Sections.Count > 0 && nodesById.ContainsKey(edge.TargetNodeId))
                      .Select(edge => new
@@ -1517,6 +1519,9 @@ public sealed class WorkflowRenderSvgRenderer
                          Points = SectionToPoints(edge.Sections.First()),
                      })
                      .Where(entry => string.Equals(entry.TargetNode.Kind, "End", StringComparison.OrdinalIgnoreCase))
+                     // Exclude corridor-rerouted edges (they route above the graph
+                     // and should render independently, not merge into a highway).
+                     .Where(entry => !entry.Points.Any(p => p.Y < graphMinY - 10d))
                      .GroupBy(entry => $"{entry.Edge.TargetNodeId}|{entry.FamilyKey}", StringComparer.Ordinal))
         {
             var entries = group.ToArray();