namespace LittleShop.Services; public interface ISystemSettingsService { Task GetSettingAsync(string key); Task GetSettingAsync(string key, T? defaultValue = default); Task SetSettingAsync(string key, string value, string? description = null); Task SetSettingAsync(string key, T value, string? description = null); Task DeleteSettingAsync(string key); Task> GetAllSettingsAsync(); Task IsTestCurrencyEnabledAsync(string currency); Task SetTestCurrencyEnabledAsync(string currency, bool enabled); }