feat(web): api client for step import/export/inline/defaults

web/app/workflows/[id]/page.tsx

@@ -84,7 +84,7 @@ export default function WorkflowBuilder() {
         return <div className="p-8 text-text-secondary">Loading…</div>;
     }
 
-    const libById = (sid: string) => library?.find((l) => l.step_id === sid);
+    const libById = (sid?: string) => (sid ? library?.find((l) => l.step_id === sid) : undefined);
 
     const sortedSteps = [...wf.steps].sort((a, b) => a.order - b.order);
     const selectedRef = selected !== null ? sortedSteps[selected] : null;