feat(localization): expand language support and enhance UI for user settings

- Added support for additional UI locales including Cebuano and Spanish, improving accessibility for a broader user base.
- Updated language selection components in the AppHeader and SettingsWidget to reflect new language options, enhancing user experience.
- Enhanced localization of various UI elements across components, ensuring consistent language representation and improved user engagement.
- Implemented logic to synchronize user language preferences with backend settings, providing a seamless experience when changing languages.

frontend/src/i18n/locales/de/settings.json

@@ -57,7 +57,8 @@
             "language": {
                 "de": "Deutsch",
                 "en": "Englisch",
-                "ceb": "Bisaya"
+                "ceb": "Bisaya",
+                "es": "Spanisch"
             },
             "eyecolor": {
                 "blue": "Blau",