Refactor frontend structure and update dependencies

- Changed the main entry point from main.jsx to main.tsx for TypeScript support.
- Removed Tabler JS import and integrated Tailwind CSS for styling.
- Updated package.json and package-lock.json to include new dependencies such as @fontsource-variable/geist and tailwindcss, while removing unused ones.
- Enhanced Vite configuration with path aliasing for improved import management.
- Deleted unused App.css and App.jsx files to streamline the project structure.

Made-with: Cursor

frontend/src/DataManager.jsx

@@ -13,8 +13,8 @@ import {
   IconDownload,
   IconUpload,
   IconAlertTriangle
-} from '@tabler/icons-react';
-import ConfirmDialog from './components/ConfirmDialog.jsx'
+} from '@/lib/icons';
+import { ConfirmDialog } from '@/components/shared/feedback'
 
 const API_URL = '/api';