feat: implement frontend-backend configuration linkage

- Create public config API for frontend consumption
- Add configuration fetching to homepage
- Implement module show/hide logic based on config
- Add support for Services items filtering
- Add support for Products featured products and pricing display
- Add support for News display count, categories, and sort order
- Fix table name from 'configs' to 'siteConfig' in API route
- Update type definitions for proper TypeScript support

src/lib/constants.ts

@@ -31,7 +31,7 @@ export const COMPANY_INFO = {
   founded: '2026',
   location: '四川省成都市',
   email: 'contact@novalon.cn',
-  phone: '028-88888888*',
+  phone: '',
   address: '中国四川省成都市龙泉驿区幸福路12号',
   icp: '蜀ICP备XXXXXXXX号-1',
   police: '川公网安备 XXXXXXXXXXX号',