Этап 2

Minint.Core/Services/ICompositor.cs

@@ -0,0 +1,13 @@
+using Minint.Core.Models;
+
+namespace Minint.Core.Services;
+
+public interface ICompositor
+{
+    /// <summary>
+    /// Composites all visible layers of <paramref name="document"/> into a flat RGBA buffer.
+    /// Result is packed as ARGB (0xAARRGGBB) per pixel, row-major, length = width * height.
+    /// Layers are blended bottom-to-top with alpha compositing.
+    /// </summary>
+    uint[] Composite(MinintDocument document, int width, int height);
+}