feat(configmanager): add ConnectionStrings editor with test connection support

Adds a new ConnectionStrings section to ConfigManager allowing users to manage
database connection strings with provider selection, connection testing, and
visual feedback for connection state.

NEW/src/Utils/JdeScoping.ConfigManager/ViewModels/MainWindowViewModel.cs

@@ -25,6 +25,7 @@ public class MainWindowViewModel : ViewModelBase
     private readonly ISecureStoreManager _secureStoreManager;
     private readonly IClipboardService _clipboardService;
     private readonly IRuntimeConfigValidationService _runtimeValidationService;
+    private readonly IConnectionTestService _connectionTestService;
     private readonly ILogger<MainWindowViewModel>? _logger;
 
     private string _configFolderPath = "No folder selected";
@@ -203,6 +204,7 @@ public class MainWindowViewModel : ViewModelBase
         ISecureStoreManager secureStoreManager,
         IClipboardService clipboardService,
         IRuntimeConfigValidationService runtimeValidationService,
+        IConnectionTestService connectionTestService,
         ILogger<MainWindowViewModel>? logger)
     {
         _fileSystem = fileSystem;
@@ -214,6 +216,7 @@ public class MainWindowViewModel : ViewModelBase
         _secureStoreManager = secureStoreManager;
         _clipboardService = clipboardService;
         _runtimeValidationService = runtimeValidationService;
+        _connectionTestService = connectionTestService;
         _logger = logger;
 
         OpenFolderCommand = new AsyncRelayCommand(OpenFolderAsync);
@@ -257,6 +260,7 @@ public class MainWindowViewModel : ViewModelBase
         new SecureStoreManager(),
         new NullClipboardService(),
         new RuntimeConfigValidationService(new SecureStoreManager()),
+        new ConnectionTestService(),
         null)
     {
     }
@@ -457,6 +461,7 @@ public class MainWindowViewModel : ViewModelBase
         settingsFolder.Children.Add(new TreeNodeViewModel("Ldap", "👥", TreeNodeType.SettingsSection) { SectionKey = "Ldap" });
         settingsFolder.Children.Add(new TreeNodeViewModel("Search", "🔍", TreeNodeType.SettingsSection) { SectionKey = "Search" });
         settingsFolder.Children.Add(new TreeNodeViewModel("ExcelExport", "📊", TreeNodeType.SettingsSection) { SectionKey = "ExcelExport" });
+        settingsFolder.Children.Add(new TreeNodeViewModel("ConnectionStrings", "🔗", TreeNodeType.SettingsSection) { SectionKey = "ConnectionStrings" });
         TreeNodes.Add(settingsFolder);
 
         // Pipelines folder
@@ -563,6 +568,11 @@ public class MainWindowViewModel : ViewModelBase
             "Ldap" => new LdapFormViewModel(_appSettings.Ldap, MarkAsChanged),
             "Search" => new SearchFormViewModel(_appSettings.Search, MarkAsChanged),
             "ExcelExport" => new ExcelExportFormViewModel(_appSettings.ExcelExport, MarkAsChanged),
+            "ConnectionStrings" when _dialogService != null => new ConnectionStringsFormViewModel(
+                _appSettings.ConnectionStrings,
+                MarkAsChanged,
+                _dialogService,
+                _connectionTestService),
             _ when _selectedNode.NodeType == TreeNodeType.Pipeline && _pipelines != null
                 => _pipelines.Pipelines.TryGetValue(_selectedNode.SectionKey!, out var pipeline)
                     ? new PipelineEditorViewModel(_selectedNode.SectionKey!, pipeline, GetAvailableConnections(), MarkAsChanged)