feat: initialize app with routing, query management, and UI framework

- Replace Vite boilerplate with React Router for page navigation
- Add React Query for server state and cache management
- Integrate shadcn/ui component library with Tailwind CSS v4
- Configure @/ path alias for clean module imports
- Set up Vite dev proxy to API backend
- Remove default App.css, App.tsx, and react.svg assets

src/lib/formatters.ts

@@ -0,0 +1,7 @@
+export function formatDateTime(iso: string): string {
+  return new Date(iso).toLocaleString()
+}
+
+export function formatDate(iso: string): string {
+  return new Date(iso).toLocaleDateString()
+}