Switch to type: classic as defalt for service workers

Because `module` doesn't work on Firefox ¬_¬
https://bugzilla.mozilla.org/show_bug.cgi?id=1360870

Author: rosa

src/core/offline.js

@@ -4,7 +4,7 @@ import { setCookie } from "../util"
 class Offline {
   serviceWorker
 
-  async start(url = "/service-worker.js", { scope = "/", type = "module", native = true } = {}) {
+  async start(url = "/service-worker.js", { scope = "/", type = "classic", native = true } = {}) {
     if (!("serviceWorker" in navigator)) {
       console.warn("Service Worker not available.")
       return