separate folders per functionality

TanksServer/Graphics/LastFinishedFrameProvider.cs

@@ -0,0 +1,14 @@
+using TanksServer.ServicePointDisplay;
+
+namespace TanksServer.Graphics;
+
+internal sealed class LastFinishedFrameProvider
+{
+    private PixelDisplayBufferView? _lastFrame;
+    
+    public PixelDisplayBufferView LastFrame
+    {
+        get => _lastFrame ?? throw new InvalidOperationException("first frame not yet drawn");
+        set => _lastFrame = value;
+    }
+}