feat: Add feature browser dock widget with document synchronization

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

src/MainWindow.cpp

@@ -2,11 +2,15 @@
 #include "ViewportWidget.h"
 #include "Document.h"
 #include "SketchFeature.h"
+#include "Feature.h"
 
 #include <QMenuBar>
 #include <QMenu>
 #include <QFileDialog>
 #include <QMessageBox>
+#include <QDockWidget>
+#include <QTreeWidget>
+#include <QTreeWidgetItem>
 #include <QToolBar>
 #include <QTabWidget>
 #include <QWidget>
@@ -80,6 +84,18 @@ MainWindow::MainWindow(QWidget *parent)
     setCentralWidget(m_viewport);
 
     m_document = new Document(this);
+    connect(m_document, &Document::featureAdded, this, &MainWindow::onFeatureAdded);
+    connect(m_document, &Document::cleared, this, &MainWindow::onDocumentCleared);
+
+    QDockWidget *dock = new QDockWidget("Browser", this);
+    addDockWidget(Qt::LeftDockWidgetArea, dock);
+
+    m_featureTree = new QTreeWidget(dock);
+    m_featureTree->setHeaderHidden(true);
+    dock->setWidget(m_featureTree);
+
+    m_rootItem = new QTreeWidgetItem(m_featureTree);
+
     setCurrentFile(QString());
 }
 
@@ -161,6 +177,22 @@ void MainWindow::setCurrentFile(const QString &fileName)
 
     QString shownName = m_currentFile;
     if (m_currentFile.isEmpty())
-        shownName = "untitled.json";
+        shownName = "Untitled";
     setWindowTitle(tr("%1[*] - %2").arg(QFileInfo(shownName).fileName(), tr("OpenCAD")));
+
+    if (m_rootItem) {
+        m_rootItem->setText(0, QFileInfo(shownName).fileName());
+    }
+}
+
+void MainWindow::onFeatureAdded(Feature* feature)
+{
+    QTreeWidgetItem *item = new QTreeWidgetItem(m_rootItem);
+    item->setText(0, feature->name());
+    m_rootItem->setExpanded(true);
+}
+
+void MainWindow::onDocumentCleared()
+{
+    qDeleteAll(m_rootItem->takeChildren());
 }