feat(core,desktop): add module detachment support to exclude from ren…

src/TextForge.Core/Documents/Document.cs

@@ -173,6 +173,25 @@ private static bool RemoveRecursive(IList<Module> list, Module target)
     #endregion
 
     #region Reordering Operations
+    public void DetachModule(Module module)
+    {
+        ArgumentNullException.ThrowIfNull(module);
+
+        if (module.Parent is not null)
+        {
+            // 1. Remove from parent collection (auto-sets module.Parent = null)
+            module.Parent.SubModules.Remove(module);
+
+            // 2. Add to root document collection
+            Modules.Add(module);
+        }
+
+        // 3. Update state
+        module.Detach();
+
+        // 4. Trigger document change pipeline
+        NotifyChanged();
+    }
 
     /// <summary>
     /// Moves a module one position earlier within its current sibling list (root level or nested level).

src/TextForge.Core/Engine/DocumentEngine.cs

@@ -1,3 +1,4 @@
+using System.Linq;
 using TextForge.Core.Documents;
 using TextForge.Core.Modules;
 using TextForge.Core.Templates;
@@ -14,6 +15,7 @@ public RenderTree Evaluate(Document document, DefaultTemplate template)
         ArgumentNullException.ThrowIfNull(template);
 
         var rootNodes = document.Modules
+            .Where(module => module.ConnectionState == ModuleConnectionState.Connected) // Skip detached root modules
             .Select(module => EvaluateModule(module, template))
             .ToList();
 
@@ -34,6 +36,7 @@ private RenderNode EvaluateModule(Module module, DefaultTemplate template)
         var resolvedLayout = template.ResolveLayout(module);
 
         var children = module.SubModules
+            .Where(child => child.ConnectionState == ModuleConnectionState.Connected) // Skip detached child modules
             .Select(child => EvaluateModule(child, template))
             .ToList();
 

src/TextForge.Core/Modules/Module.cs

@@ -13,6 +13,7 @@ public class Module : INotifyPropertyChanged
     private bool _isExpanded;
     private Module? _parent;
 
+    private ModuleConnectionState _connectionState = ModuleConnectionState.Connected;
     public event PropertyChangedEventHandler? PropertyChanged;
 
     public Guid Id { get; init; } = Guid.NewGuid();
@@ -109,6 +110,31 @@ private void WireSubModulesCollection()
         SubModules.CollectionChanged += OnSubModulesChanged;
     }
 
+    /// <summary>
+    /// Dictates whether the module is actively part of the document flow or temporarily detached.
+    /// Detached modules retain all data and children but are skipped during PDF rendering.
+    /// </summary>
+    public ModuleConnectionState ConnectionState
+    {
+        get => _connectionState;
+        set
+        {
+            if (_connectionState != value)
+            {
+                _connectionState = value;
+                OnPropertyChanged();
+                OnPropertyChanged(nameof(IsDetached));
+            }
+        }
+    }
+
+    [JsonIgnore]
+    public bool IsDetached => ConnectionState == ModuleConnectionState.Detached;
+
+    // Helper toggle methods
+    public void Detach() => ConnectionState = ModuleConnectionState.Detached;
+    public void Connect() => ConnectionState = ModuleConnectionState.Connected;
+
     private void OnSubModulesChanged(object? sender, NotifyCollectionChangedEventArgs e)
     {
         if (e.NewItems != null)

src/TextForge.Core/Modules/ModuleConnectionState.cs

@@ -0,0 +1,17 @@
+namespace TextForge.Core.Modules;
+
+/// <summary>
+/// Dictates whether a module participates in the document layout.
+/// </summary>
+public enum ModuleConnectionState
+{
+    /// <summary>
+    /// The module is part of the layout and will be rendered.
+    /// </summary>
+    Connected,
+
+    /// <summary>
+    /// The module is preserved in the document model but excluded from layout and rendering.
+    /// </summary>
+    Detached
+}

src/TextForge.Desktop/Views/Components/ModuleEditorView.axaml

@@ -90,13 +90,13 @@
                                     Background="Transparent" Foreground="#EF4444"
                                     ToolTip.Tip="Delete Module"
                                     Tag="{Binding}" Click="DeleteModuleButton_Click" />
-                                <Button Content="+" FontSize="14" FontWeight="Bold" Width="22"
+                                <Button Content="⊘" FontSize="14" FontWeight="Bold" Width="22"
                                     Height="22" Padding="0"
                                     HorizontalContentAlignment="Center"
                                     VerticalContentAlignment="Center"
-                                    Background="Transparent" Foreground="#10B981"
-                                    ToolTip.Tip="Duplicate Module"
-                                    Tag="{Binding}" Click="DuplicateModuleButton_Click" />
+                                    Background="Transparent" Foreground="#F59E0B"
+                                    ToolTip.Tip="Detach from layout"
+                                    Tag="{Binding}" Click="DetachModuleButton_Click" />
 
                             </StackPanel>
                         </Grid>

src/TextForge.Desktop/Views/Components/ModuleEditorView.axaml.cs

@@ -14,6 +14,8 @@
     public event EventHandler<Module>? ModuleMoveDownRequested;
     public event EventHandler<Module>? ModuleDeleteRequested;
     public event EventHandler<Module>? ModuleDuplicateRequested;
+    public event EventHandler<Module>? ModuleDetachRequested;
+    public event EventHandler<Module>? ModuleReconnectRequested;
 
     public ModuleEditorView()
     {
@@ -51,6 +53,13 @@
             ModuleDuplicateRequested?.Invoke(this, module);
         }
     }
+    private void DetachModuleButton_Click(object? sender, RoutedEventArgs e)
+    {
+        if (sender is Button { Tag: Module module })
+        {
+            ModuleDetachRequested?.Invoke(this, module);
+        }
+    }
 
     /// <summary>
     /// Binds the editor to a document instance.

src/TextForge.Desktop/Views/MainWindow.axaml.cs

@@ -96,7 +96,7 @@ private void BindModuleList()
         moduleEditor.ModuleMoveDownRequested += ModuleEditor_ModuleMoveDownRequested;
         moduleEditor.ModuleDeleteRequested += ModuleEditor_ModuleDeleteRequested;
         moduleEditor.ModuleDuplicateRequested += ModuleEditor_ModuleDuplicateRequested;
-
+        moduleEditor.ModuleDetachRequested += ModuleEditor_ModuleDetachRequested;
 
         var moduleListBox = moduleEditor.FindControl<ListBox>("ModuleListBox");
         if (moduleListBox is not null)
@@ -206,6 +206,15 @@ private void ModuleEditor_ModuleDuplicateRequested(object? sender, Module module
         }
     }
 
+    private void ModuleEditor_ModuleDetachRequested(object? sender, Module module)
+    {
+        if (_currentDocument is not null)
+        {
+            _currentDocument.DetachModule(module);
+            RefreshModuleEditorList();
+        }
+    }
+
     #endregion
 
     #region Document & Preview Synchronization