fix(ui): keep execution overlay active when drilled down into sub-routes

ui/src/components/ProcessDiagram/ProcessDiagram.tsx

@@ -69,10 +69,10 @@ export function ProcessDiagram({
   const currentRouteId = routeStack[routeStack.length - 1];
   const isDrilledDown = currentRouteId !== routeId;
 
-  // Disable overlay when drilled down — the execution data is for the root route
-  // and doesn't map to sub-route node IDs. Sub-route shows topology only.
-  const overlayActive = !!executionOverlay && !isDrilledDown;
-  const effectiveOverlay = isDrilledDown ? undefined : executionOverlay;
+  // Keep overlay active when drilled down — the execution tree includes
+  // sub-route processors as nested children, so their IDs are in the overlay map.
+  const overlayActive = !!executionOverlay;
+  const effectiveOverlay = executionOverlay;
 
   // Only use the pre-fetched diagramLayout for the root route.
   const effectiveLayout = isDrilledDown ? undefined : diagramLayout;