fix: Include node_states from SSE events in frontend result

- Add node_states field to finalResult from execution_complete event
- Add node_states to execution_failed for partial progress visibility
- Remove TODO comment and empty array placeholder
- Enables WorkflowDebugPanel to receive actual node data

Fixes: Debug panel not appearing due to empty node_states array

frontend/src/utils/api.js

@@ -445,13 +445,25 @@ export const api = {
               execution_id: data.execution_id,
               status: data.status,
               aggregated_result: data.aggregated_result,
+              node_states: data.node_states || [],  // Include node_states from SSE
               debug: {
-                node_states: []  // TODO: collect from progress events if needed
+                node_states: data.node_states || []
               }
             }
             eventSource.close()
             resolve(finalResult)
           } else if (data.type === 'execution_failed') {
+            // Include partial node_states if available
+            finalResult = {
+              type: 'workflow',
+              execution_id: data.execution_id,
+              status: 'failed',
+              error: data.error,
+              node_states: data.node_states || [],
+              debug: {
+                node_states: data.node_states || []
+              }
+            }
             eventSource.close()
             reject(new Error(data.error || 'Workflow execution failed'))
           }