fix: admin pricing page endpoint, JSX structure fixes

- pricing: change /api/admin/tracecoin-packages to /api/admin/packages
- modules.tsx: wrap with fragment, fix heading structure
- [...module].tsx: fix missing container div
- DashboardDesignPreview.tsx: fix '>' in text

src/routes/admin/pricing.tsx

@@ -29,7 +29,7 @@ const ROLES = [
 
 async function loadPackages(): Promise<Package[]> {
   try {
-    const res = await fetch(`${API}/api/admin/tracecoin-packages`);
+    const res = await fetch(`${API}/api/admin/packages`);
     if (!res.ok) throw new Error('Failed to load');
     const data = await res.json();
     return Array.isArray(data) ? data : (data.packages || []);