refactor(web): add Redux state management and centralised routing

- Replace inline BrowserRouter with createBrowserRouter and lazy-loaded pages
- Add Redux store with auth-slice (token management) and redux-persist
- Create RequireAuth guard using Redux state via isAuthenticated selector
- Wire Layout logout to dispatch setToken("") clearing persisted auth
- Add ErrorPage component for route error handling
- Add EmptyLayout for unauthenticated pages
- Add VITE_REDUX_STORAGE env var for storage selection

web/.env.example

@@ -11,3 +11,7 @@
 #   Default: https://pipely.onixbyte.com/
 #   Development: http://localhost:8080
 VITE_API_BASE_URL=https://pipely.onixbyte.com/
+
+# Redux Persistent storage location
+#   Options: `local` (default), `session`
+VITE_REDUX_STORAGE=local