feat: update main chat and system chat UI

src/components/chatActivityExecutor/samples/VerificationSample.tsx

@@ -0,0 +1,24 @@
+import type { SampleMeta } from '../../../widgets/core';
+import { ExecutorActivityCardSample } from '../sampleShared';
+
+export const sampleMeta: SampleMeta = {
+  id: 'chat-activity-executor-verification',
+  componentId: 'chat-activity-executor-verification',
+  title: 'Chat Activity Executor Verification',
+  description: '검증 단계 실행기 문구 샘플입니다.',
+  category: 'Chat',
+  kind: 'feature',
+  order: 13,
+  features: ['component-sample'],
+};
+
+export function Sample() {
+  return (
+    <ExecutorActivityCardSample
+      title="검증 문구"
+      focus="시스템 Plan 체크리스트 문구 개선"
+      command="npm run capture:component -- chat-activity-executor-verification 2026-05-18"
+      description="스크린샷 캡처나 최종 확인 단계는 검증 문구로 명확하게 구분합니다."
+    />
+  );
+}