TASK 4 ship step 5: live frame pipeline — FramePump paces the active scene's composite into the encoder, ScreenCaptureManager.GetLatestFrame, MainViewModel resolver/option-builder/pump wiring, FramePumpTests (7) + GetLatestFrame test — 147 tests passing, 0 warnings

ytLive.Tests/ScreenCaptureManagerTests.cs

@@ -145,6 +145,28 @@ public class ScreenCaptureManagerTests
         Assert.False(await manager.AcquireAsync(" "));
     }
 
+    [Fact]
+    public async Task GetLatestFrame_ReturnsLatestPump_UntilReleased()
+    {
+        FakeScreenSource? captured = null;
+        var manager = new ScreenCaptureManager(key => captured = new FakeScreenSource(key));
+
+        Assert.Null(manager.GetLatestFrame("monitor:0"));
+
+        Assert.True(await manager.AcquireAsync("monitor:0"));
+        Assert.Null(manager.GetLatestFrame("monitor:0")); // nothing pumped yet
+
+        var first = new VideoFrame(2, 2, Pixels(1, 0, 0, 255, 2, 0, 0, 255, 3, 0, 0, 255, 4, 0, 0, 255));
+        var second = new VideoFrame(2, 2, Pixels(5, 0, 0, 255, 6, 0, 0, 255, 7, 0, 0, 255, 8, 0, 0, 255));
+        captured!.Pump(first);
+        captured.Pump(second);
+
+        Assert.Same(second, manager.GetLatestFrame("monitor:0"));
+
+        await manager.ReleaseAsync("monitor:0");
+        Assert.Null(manager.GetLatestFrame("monitor:0"));
+    }
+
     // The one integration test for this branch: one target creates one shared
     // WriteableBitmap, published once, and back-to-back frames coalesce to the
     // latest (a single pending UI copy per session).