refactor(frontend): frontend-embed/src/to-be-sharedを共通化 (#14536)

* refactor(frontend): shouldCollapsedを共通化

* refactor(frontend): config.js, worker-multi-dispatch.js, intl-const.jsを共通化

* fix(frontend-shared): fix type error

* refactor(frontend): is-link.jsと、同一の振る舞いをする記述を共通化

* fix

* fix lint

* lint fixes

packages/frontend/src/scripts/intl-const.ts

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { lang } from '@/config.js';
+import { lang } from '@@/js/config.js';
 
 export const versatileLang = (lang ?? 'ja-JP').replace('ja-KS', 'ja-JP');