refactor: 拆分 constants.ts 为多个模块文件

src/lib/constants/index.ts

@@ -0,0 +1,7 @@
+export { COMPANY_INFO } from './company';
+export { NAVIGATION, type NavigationItem } from './navigation';
+export { STATS, type StatItem } from './stats';
+export { SERVICES } from './services';
+export { PRODUCTS } from './products';
+export { NEWS, type NewsItem, type NewsCategory } from './news';
+export { CASES } from './cases';