Social bar v2: fediverse icons resolved via nodeinfo (with redirect-following), persisted software column, icon colors — 112 tests passing, 0 warnings

MainWindow.xaml.cs

@@ -254,6 +254,44 @@ public partial class MainWindow : Window
     private void OpacitySlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
         => OpacityValueText.Text = $"{Math.Round(e.NewValue * 100)}%";
 
+    // ─── Social bar drag: vertical only, snaps to top/bottom on release ───
+    private const double SocialBarBottomTop = 1040;
+    private bool _isDraggingSocialBar;
+    private double _socialBarGrabOffsetY;
+
+    private void SocialBar_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        var bar = (FrameworkElement)sender;
+        _isDraggingSocialBar = true;
+        var toCanvas = CanvasGrid.TransformToVisual(bar).Inverse;
+        var p = toCanvas.Transform(e.GetPosition(bar));
+        _socialBarGrabOffsetY = p.Y - Canvas.GetTop(bar);
+        bar.CaptureMouse();
+        e.Handled = true;
+    }
+
+    private void SocialBar_PreviewMouseMove(object sender, MouseEventArgs e)
+    {
+        if (!_isDraggingSocialBar) return;
+        var bar = (FrameworkElement)sender;
+        var toCanvas = CanvasGrid.TransformToVisual(bar).Inverse;
+        var p = toCanvas.Transform(e.GetPosition(bar));
+        Canvas.SetTop(bar, Math.Clamp(p.Y - _socialBarGrabOffsetY, 0, SocialBarBottomTop));
+        e.Handled = true;
+    }
+
+    private void SocialBar_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (!_isDraggingSocialBar) return;
+        var bar = (FrameworkElement)sender;
+        var top = Canvas.GetTop(bar);
+        bar.ReleaseMouseCapture();
+        _isDraggingSocialBar = false;
+        var position = top <= SocialBarBottomTop / 2.0 ? SocialBarPosition.Top : SocialBarPosition.Bottom;
+        _viewModel.SetSocialBarPosition(position);
+        e.Handled = true;
+    }
+
     private void Preview_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
     {
         if (OpacityChip.IsMouseOver) return;