Desktop installer: show release channel in its own group box

Same style as the other radio groups, placed below the drive selection.

desktop/OmniNX.DesktopInstaller/MainForm.cs

@@ -54,7 +54,7 @@ public sealed class MainForm : Form
         {
             Dock = DockStyle.Fill,
             ColumnCount = 1,
-            RowCount = 8,
+            RowCount = 9,
             Padding = new Padding(12),
         };
         root.RowStyles.Add(new RowStyle(SizeType.AutoSize));
@@ -64,16 +64,18 @@ public sealed class MainForm : Form
         root.RowStyles.Add(new RowStyle(SizeType.AutoSize));
         root.RowStyles.Add(new RowStyle(SizeType.AutoSize));
         root.RowStyles.Add(new RowStyle(SizeType.AutoSize));
+        root.RowStyles.Add(new RowStyle(SizeType.AutoSize));
         root.RowStyles.Add(new RowStyle(SizeType.Percent, 100));
 
         root.Controls.Add(BuildHeaderPanel(), 0, 0);
         root.Controls.Add(BuildDrivePanel(), 0, 1);
-        root.Controls.Add(BuildVariantPanel(), 0, 2);
-        root.Controls.Add(BuildRamPanel(), 0, 3);
-        root.Controls.Add(BuildHekatePanel(), 0, 4);
-        root.Controls.Add(BuildOptionsPanel(), 0, 5);
-        root.Controls.Add(BuildActionPanel(), 0, 6);
-        root.Controls.Add(BuildLogPanel(), 0, 7);
+        root.Controls.Add(BuildChannelPanel(), 0, 2);
+        root.Controls.Add(BuildVariantPanel(), 0, 3);
+        root.Controls.Add(BuildRamPanel(), 0, 4);
+        root.Controls.Add(BuildHekatePanel(), 0, 5);
+        root.Controls.Add(BuildOptionsPanel(), 0, 6);
+        root.Controls.Add(BuildActionPanel(), 0, 7);
+        root.Controls.Add(BuildLogPanel(), 0, 8);
 
         Controls.Add(root);
     }
@@ -85,11 +87,10 @@ public sealed class MainForm : Form
             AutoSize = true,
             Dock = DockStyle.Fill,
             ColumnCount = 1,
-            RowCount = 3,
+            RowCount = 2,
         };
         panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
         panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
-        panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
 
         var title = new Label
         {
@@ -120,27 +121,25 @@ public sealed class MainForm : Form
         releaseRow.Controls.Add(_releaseLabel);
         releaseRow.Controls.Add(_checkReleaseButton);
 
-        // Release channel: stable releases or the master build (internal testing)
-        _channelRelease = new RadioButton { Text = "Release", AutoSize = true, Checked = true, Margin = new Padding(0, 0, 16, 0) };
-        _channelMaster = new RadioButton { Text = "Master (Instabil)", AutoSize = true, ForeColor = Color.DarkOrange };
+        panel.Controls.Add(title, 0, 0);
+        panel.Controls.Add(releaseRow, 0, 1);
+        return panel;
+    }
+
+    // Release channel: stable releases or the master build (internal testing)
+    private Control BuildChannelPanel()
+    {
+        var group = new GroupBox { Text = "Release Channel", Dock = DockStyle.Fill, AutoSize = true, Padding = new Padding(10) };
+        var flow = new FlowLayoutPanel { Dock = DockStyle.Fill, AutoSize = true };
+
+        _channelRelease = new RadioButton { Text = "Release", AutoSize = true, Checked = true, Margin = new Padding(0, 0, 24, 0) };
+        _channelMaster = new RadioButton { Text = "Master (Instabil)", AutoSize = true };
         _channelRelease.CheckedChanged += OnChannelChanged;
         _channelMaster.CheckedChanged += OnChannelChanged;
 
-        var channelRow = new FlowLayoutPanel
-        {
-            AutoSize = true,
-            WrapContents = false,
-            Dock = DockStyle.Fill,
-            Margin = new Padding(0, 0, 0, 4),
-        };
-        channelRow.Controls.Add(new Label { Text = "Channel:", AutoSize = true, Anchor = AnchorStyles.Left, Margin = new Padding(0, 3, 8, 0) });
-        channelRow.Controls.Add(_channelRelease);
-        channelRow.Controls.Add(_channelMaster);
-
-        panel.Controls.Add(title, 0, 0);
-        panel.Controls.Add(releaseRow, 0, 1);
-        panel.Controls.Add(channelRow, 0, 2);
-        return panel;
+        flow.Controls.AddRange([_channelRelease, _channelMaster]);
+        group.Controls.Add(flow);
+        return group;
     }
 
     private ReleaseChannel SelectedChannel =>