feat(frontend): セーフモード (#16245)

* feat(frontend): セーフモード

* Update Changelog

* Update Changelog

* fix

* fix

* Update Changelog

* Update Changelog

* PWAのショートカット経由でもセーフモードで起動できるように

* Update ClientServerService.ts

---------

Co-authored-by: syuilo <4439005+syuilo@users.noreply.github.com>

packages/frontend-shared/js/config.ts

@@ -23,6 +23,7 @@ export const version = _VERSION_;
 export const instanceName = (siteName === 'Misskey' || siteName == null) ? host : siteName;
 export const ui = localStorage.getItem('ui');
 export const debug = localStorage.getItem('debug') === 'true';
+export const isSafeMode = localStorage.getItem('isSafeMode') === 'true';
 
 export function updateLocale(newLocale: Locale): void {
 	locale = newLocale;