fix(auth): prevent login redirect loop and concurrent refresh calls

- Added check to avoid redirecting to `/login` if already on the login page.
- Prevented multiple simultaneous `refreshUser` calls by adding an `isLoading` guard.
- Improved `useEffect` cleanup in `auth-provider` to handle components unmounting.

frontend/src/lib/api.ts

@@ -53,7 +53,10 @@ api.interceptors.response.use(
 			} catch (refreshError) {
 				// If refresh fails, we might want to redirect to login on the client
 				if (typeof window !== "undefined") {
-					window.location.href = "/login";
+					// On évite de rediriger vers login si on y est déjà pour éviter les boucles
+					if (!window.location.pathname.includes("/login")) {
+						window.location.href = "/login";
+					}
 				}
 				return Promise.reject(refreshError);
 			}