Fix: add codeexec attachments output (#14787)

### What problem does this PR solve?

add codeexec attachments output

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/pages/agent/form-sheet/single-debug-sheet/utils.ts

@@ -4,6 +4,7 @@ import { CodeOutputContract } from '../../form/code-form/utils';
 const SYSTEM_OUTPUT_NAMES = new Set([
   '_ERROR',
   '_ARTIFACTS',
+  'attachments',
   '_ATTACHMENT_CONTENT',
 ]);