refactor: reorganize shared/lib into per-function subfolders

src/shared/lib/index.ts

@@ -1,6 +1,6 @@
 export type { ClassValue } from 'clsx';
-export { cn } from './cn';
-export { CONTACT_LINKS } from './config';
-export * from './fonts';
-export * from './formatDate';
-export { groupByKey } from './groupByKey';
+export { CONTACT_LINKS } from './config/config';
+export * from './fonts/fonts';
+export { cn } from './utils/cn/cn';
+export * from './utils/formatDate/formatDate';
+export { groupByKey } from './utils/groupByKey/groupByKey';