transform admin panel with comprehensive professional UI

- migrate from SQLite to PostgreSQL with Drizzle ORM
- implement comprehensive AdminLayout with expandable sidebar navigation
- create professional dashboard with real-time charts and metrics
- add advanced monitoring, reporting, and export functionality
- fix menu alignment and remove non-existent pages
- eliminate duplicate headers and improve UI consistency
- add Tailwind CSS v3 for professional styling
- expand database schema from 6 to 15 tables
- implement role-based access control and API key management
- create comprehensive settings, monitoring, and system info pages

pages/api/sources/check.ts

@@ -117,7 +117,7 @@ export default async function handler(
         source_count: 0
       }
     } else {
-      const maxRiskLevel = Math.max(...sources.map(s => s.riskLevel))
+      const maxRiskLevel = Math.max(...sources.map(s => s.riskLevel || 0))
       const allCategories = sources
         .map(s => s.categories)
         .filter(Boolean)