Transitions: Wipe (left-to-right reveal), added to the App Settings picker

Test: WipeTransitionTests. Not pushed.

ytLive.Tests/WipeTransitionTests.cs

@@ -0,0 +1,25 @@
+using System.Linq;
+using Xunit;
+using ytLive.Services;
+
+namespace ytLive.Tests;
+
+public class WipeTransitionTests
+{
+    [Fact]
+    public void Wipe_At_Half_Reveals_The_New_Scene_On_The_Left_Half()
+    {
+        var transition = new TransitionService();
+        var to = new VideoFrame(4, 1, Enumerable.Repeat((byte)255, 16).ToArray());
+        var from = new VideoFrame(4, 1, new byte[16]);
+
+        transition.Start(TransitionType.Wipe, 300, from);
+        transition.Tick(150);
+        var blended = transition.BlendFrame(to);
+
+        Assert.Equal((byte)255, blended.BgraPixels[0]);
+        Assert.Equal((byte)255, blended.BgraPixels[4]);
+        Assert.Equal((byte)0, blended.BgraPixels[8]);
+        Assert.Equal((byte)0, blended.BgraPixels[12]);
+    }
+}