UI: #334 add config page language setting (#374)

* UI: #334 add config page language setting

* temporary remove logout button

* Unify fullscreen view class for dialog expanded and settings view

- Replace dialog-expanded and settings-view with single fullscreen-view class
- Update ResponsiveDialog to use fullscreen-view class
- Update CalendarLayout to use fullscreen-view class for settings view
- Consolidate CSS rules in Menubar.styl to use fullscreen-view
- Update test cases to use new class name

---------

Co-authored-by: Lê Nhân Phụng <lenhanphung@Phung-Mac-M4.local>

src/utils/userUtils.ts

@@ -0,0 +1,19 @@
+import { userData } from "../features/User/userDataTypes";
+
+/**
+ * Get user display name for UI display
+ * Returns full name if available, otherwise email, or empty string as fallback
+ * @param user - User data object
+ * @returns Display name string
+ */
+export function getUserDisplayName(user: userData | null | undefined): string {
+  if (!user) {
+    return "";
+  }
+
+  if (user.name && user.family_name) {
+    return `${user.name} ${user.family_name}`;
+  }
+
+  return user.email || "";
+}