feat: Add Instance Details ViewModel and UI for managing instance credentials

- Introduced InstanceDetailsViewModel to handle loading and displaying instance-specific credentials.
- Created InstanceDetailsWindow and associated XAML for displaying admin, database, and OAuth2 credentials.
- Updated InstancesViewModel to include command for opening instance details.
- Enhanced SettingsViewModel to manage Bitwarden and Xibo Bootstrap configurations, including connection testing.
- Added UI components for Bitwarden Secrets Manager and Xibo Bootstrap OAuth2 settings in the SettingsView.
- Implemented password visibility toggles and clipboard copy functionality for sensitive information.

OTSSignsOrchestrator.Desktop/App.axaml.cs

@@ -114,6 +114,8 @@ public class App : Application
         // HTTP
         services.AddHttpClient();
         services.AddHttpClient("XiboApi");
+        services.AddHttpClient("XiboHealth");
+        services.AddHttpClient("Bitwarden");
 
         // SSH services (singletons — maintain connections)
         services.AddSingleton<SshConnectionService>();
@@ -131,11 +133,14 @@ public class App : Application
         services.AddTransient<ComposeValidationService>();
         services.AddTransient<XiboApiService>();
         services.AddTransient<InstanceService>();
+        services.AddTransient<IBitwardenSecretService, BitwardenSecretService>();
+        services.AddSingleton<PostInstanceInitService>();
 
         // ViewModels
         services.AddTransient<MainWindowViewModel>();
         services.AddTransient<HostsViewModel>();
         services.AddTransient<InstancesViewModel>();
+        services.AddTransient<InstanceDetailsViewModel>();
         services.AddTransient<CreateInstanceViewModel>();
         services.AddTransient<SecretsViewModel>();
         services.AddTransient<SettingsViewModel>();