fix(auth): preserve session on reload and correct 401 redirect flow

- Save PKCE params to sessionStorage.redirectState on 401 instead of overwriting tokenSet

- Persist userData in sessionStorage after OIDC callback for later hydration

- Hydrate Redux (tokens + userData) from sessionStorage on app start to avoid forced re-login

- Keep SPA single route '/' behavior unchanged; only improves auth robustness

Files: src/utils/apiUtils.ts, src/features/User/LoginCallback.tsx, src/features/User/HandleLogin.tsx

src/features/User/LoginCallback.tsx

@@ -27,6 +27,7 @@ export function CallbackResume() {
 
         sessionStorage.removeItem("redirectState");
         sessionStorage.setItem("tokenSet", JSON.stringify(data?.tokenSet));
+        sessionStorage.setItem("userData", JSON.stringify(data?.userinfo));
         // Redirect to main page after successful callback
         dispatch(push("/"));
       } catch (e) {