Use throw instead of return Promise.reject in async error handlers (S7746)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/api/client.js

@@ -56,7 +56,7 @@ apiClient.interceptors.response.use(
       originalRequest._retried ||
       originalRequest.url === "/api/oauth/token"
     ) {
-      return Promise.reject(error);
+      throw error;
     }
 
     if (isRefreshing) {
@@ -91,7 +91,7 @@ apiClient.interceptors.response.use(
       deleteCookie("luciaRefreshToken");
       deleteCookie("isLuciaLoggedIn");
       globalThis.location.href = "/login";
-      return Promise.reject(refreshError);
+      throw refreshError;
     }
   },
 );