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/es/falukant.json

@@ -430,7 +430,9 @@
                 "selectStockType": "Seleccionar tipo de almacén",
                 "costPerUnit": "Coste por unidad",
                 "buycost": "Coste",
-                "sellincome": "Ingresos"
+                "sellincome": "Ingresos",
+                "buyPartialError": "Error al comprar parte de la capacidad del almacén.",
+                "sellError": "Error al vender la capacidad del almacén."
             },
             "vehicles": {
                 "cargo_cart": "Carro de carga",