feat: i18n 개선 및 userfront 로그인/로케일 보완

userfront/test/helpers/web_storage.dart

@@ -0,0 +1,5 @@
+import 'web_storage_stub.dart'
+    if (dart.library.html) 'web_storage_web.dart';
+
+export 'web_storage_stub.dart'
+    if (dart.library.html) 'web_storage_web.dart';

userfront/test/helpers/web_storage_stub.dart

@@ -0,0 +1,21 @@
+class WebStorage {
+  bool get isWeb => false;
+
+  String? get(String key) => null;
+
+  void set(String key, String value) {}
+
+  String? getSession(String key) => null;
+
+  void setSession(String key, String value) {}
+
+  void removeSession(String key) {}
+
+  void clearSession() {}
+
+  void remove(String key) {}
+
+  void clear() {}
+}
+
+final webStorage = WebStorage();

userfront/test/helpers/web_storage_web.dart

@@ -0,0 +1,37 @@
+// ignore_for_file: avoid_web_libraries_in_flutter
+
+import 'dart:html' as html;
+
+class WebStorage {
+  bool get isWeb => true;
+
+  String? get(String key) => html.window.localStorage[key];
+
+  void set(String key, String value) {
+    html.window.localStorage[key] = value;
+  }
+
+  String? getSession(String key) => html.window.sessionStorage[key];
+
+  void setSession(String key, String value) {
+    html.window.sessionStorage[key] = value;
+  }
+
+  void removeSession(String key) {
+    html.window.sessionStorage.remove(key);
+  }
+
+  void clearSession() {
+    html.window.sessionStorage.clear();
+  }
+
+  void remove(String key) {
+    html.window.localStorage.remove(key);
+  }
+
+  void clear() {
+    html.window.localStorage.clear();
+  }
+}
+
+final webStorage = WebStorage();