feat: LAD A-Team CIS Compliance Report, React SPA, i18n, report management, explorer UX fixes

- Professional Oracle-format compliance report with RAG remediation from ADB vector store
- React 19 SPA at /app/ (16 pages, TypeScript, Vite, Zustand, i18n pt/en 625 keys)
- Report delete endpoint, embed individual report files into vector store
- Terraform ZIP download (client-side, pure JS)
- Explorer silent polling during start/stop (no flickering)
- HTML report and compliance report sections start minimized
- Token auth fix for compliance report CSV download links

frontend-react/src/components/layout/AppShell.tsx

@@ -0,0 +1,27 @@
+import { Outlet, Navigate } from 'react-router-dom';
+import { useAuthStore } from '@/stores/auth';
+import Sidebar from './Sidebar';
+
+export default function AppShell() {
+  const { user, loading } = useAuthStore();
+
+  if (loading) {
+    return (
+      <div className="flex items-center justify-center h-screen" style={{ background: 'var(--bg)' }}>
+        <div className="animate-spin w-8 h-8 rounded-full border-2 border-t-transparent"
+          style={{ borderColor: 'var(--ac)', borderTopColor: 'transparent' }} />
+      </div>
+    );
+  }
+
+  if (!user) return <Navigate to="/login" replace />;
+
+  return (
+    <div className="flex h-screen overflow-hidden">
+      <Sidebar />
+      <main className="flex-1 ml-[260px] overflow-y-auto h-screen" style={{ background: 'var(--bg)' }}>
+        <Outlet />
+      </main>
+    </div>
+  );
+}