fix: only show amber on containers where gate blocked all children

A container is only gated (amber) when filterMatched=false or
duplicateMessage=true AND no descendants were executed. Containers
with executed children (split, choice, idempotent that passed) now
correctly show green/red based on their execution status.

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

ui/src/components/ProcessDiagram/CompoundNode.tsx

@@ -68,10 +68,14 @@ export function CompoundNode({
 
   // Execution overlay state for this compound
   const ownState = node.id ? executionOverlay?.get(node.id) : undefined;
-  const isGated = ownState?.filterMatched === false || ownState?.duplicateMessage === true;
+  const hasExecutedChild = ownState && hasExecutedDescendant(node, executionOverlay);
   const isCompleted = ownState?.status === 'COMPLETED';
   const isFailed = ownState?.status === 'FAILED';
 
+  // Gated = gate processor (filter/idempotent) blocked all children from executing
+  const isGated = ownState && !hasExecutedChild
+    && (ownState.filterMatched === false || ownState.duplicateMessage === true);
+
   // Color priority: gated (amber) > failed (red) > completed (green) > default
   const effectiveColor = isGated ? 'var(--amber)'
     : isFailed ? '#C0392B'