refactor: Refactor feature browser, move to top-left, and increase font size

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

src/FeatureBrowser.cpp

@@ -0,0 +1,61 @@
+#include "FeatureBrowser.h"
+#include "Document.h"
+#include "Feature.h"
+
+#include <algorithm>
+#include <QFont>
+#include <QPainter>
+
+FeatureBrowser::FeatureBrowser()
+{
+}
+
+void FeatureBrowser::setDocument(Document* document)
+{
+    m_document = document;
+}
+
+void FeatureBrowser::paint(QPainter& painter, int viewportWidth, int viewportHeight)
+{
+    if (!m_document) {
+        return;
+    }
+
+    painter.setRenderHint(QPainter::Antialiasing);
+    painter.setFont(QFont("Arial", 12));
+
+    const int padding = 5;
+    const int margin = 10;
+    int x = margin;
+    int y = margin;
+    int lineHeight = painter.fontMetrics().height();
+    const QList<Feature*>& features = m_document->features();
+    QString docName = m_document->fileName();
+
+    int maxWidth = painter.fontMetrics().horizontalAdvance(docName);
+
+    for (const Feature* feature : features) {
+        maxWidth = std::max(maxWidth, painter.fontMetrics().horizontalAdvance("  " + feature->name()));
+    }
+
+    int boxWidth = maxWidth + 2 * padding;
+    int boxHeight = (features.size() + 1) * lineHeight + 2 * padding;
+
+    // Draw transparent background
+    painter.setPen(Qt::NoPen);
+    painter.setBrush(QColor(50, 50, 50, 150));
+    painter.drawRoundedRect(x, y, boxWidth, boxHeight, 3, 3);
+
+    // Draw text
+    painter.setPen(Qt::white);
+    int currentY = y + padding + lineHeight;
+    int textX = x + padding;
+
+    painter.drawText(textX, currentY, docName);
+    currentY += lineHeight;
+
+    for (const Feature* feature : features) {
+        painter.drawText(textX + 10, currentY, feature->name());
+        currentY += lineHeight;
+    }
+}