Working React 19 before Compiler integration

🚀 Phase 2 Complete - React 19 Foundation
- React upgraded: 18.2.0 → 19.0.0 ✅
- MUI upgraded: 5 → 6 ✅
- React Router upgraded: 6 → 7 ✅
- All packages updated and working ✅
- Production build: 995KB bundle ✅
- All containers working ✅

Ready for Phase 3: React Compiler integration

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/vite.config.ts

@@ -12,5 +12,10 @@ export default defineConfig({
   server: {
     port: 3000,
     host: '0.0.0.0', // Allow external connections for container
+    allowedHosts: [
+      'localhost',
+      'motovaultpro.com',
+      '.motovaultpro.com'
+    ],
   },
 });