Recording settings: open focused on the first checkbox, not the option columns

The dialog set sourceList.TabIndex=0, so it grabbed initial focus and the user landed partway
down, past the two new toggles. Put the toggles first in tab order (and ordered the containers,
so the top row precedes the grid), and force focus to the split-tracks checkbox on show.

Held for next release.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/RemSound.App/RecordingSettingsDialog.cs

@@ -306,6 +306,14 @@ internal sealed class RecordingSettingsDialog : Form
         // sits between attributes and channels in tab order so the Alt+L mnemonic and Tab
         // both land there when it's visible; when hidden it's still in tab order but
         // skipped because Visible=false controls aren't focusable.
+        // The two toggles (top of the dialog) come first in tab order, then the option columns, then
+        // the buttons. The CONTAINERS are ordered too — without this the grid's controls (sourceList)
+        // sat first and grabbed initial focus, landing the user partway down, past the checkboxes.
+        optionsRow.TabIndex = 0;
+        grid.TabIndex = 1;
+        buttonRow.TabIndex = 2;
+        splitTracksBox.TabIndex = 0;
+        bypassShapingBox.TabIndex = 1;
         sourceList.TabIndex = 0;
         formatList.TabIndex = 1;
         attributesList.TabIndex = 2;
@@ -315,6 +323,13 @@ internal sealed class RecordingSettingsDialog : Form
         cancelButton.TabIndex = 6;
     }
 
+    protected override void OnShown(EventArgs e)
+    {
+        base.OnShown(e);
+        // Land on the first checkbox at the top, not partway down on the option columns.
+        splitTracksBox.Focus();
+    }
+
     /// <summary>Show or hide the FLAC compression column based on the current file-format
     /// selection. Driven from the formatList change handler and once at dialog open.
     /// When hidden, the column's ColumnStyle width is set to 0% and the other four columns