Render graph: native pass merging & heap-based aliasing

Major architecture upgrade:
- Add native render pass merging (hardware pass grouping, load/store op inference)
- Implement heap-based aliasing for textures & buffers (D3D12-style)
- Unify resource model: buffers and textures in one registry
- Extend builder API for buffer creation/usage, access flags, hints
- Improve barrier/state tracking (buffer hints, indirect argument state)
- Update caching, hashing, and debug output for new model
- Add enums/structs: AttachmentLoadOp, StoreOp, BufferHint, etc.
- D3D12 backend: support named resources, temp upload buffers, correct heap usage
- Update docs, benchmarks, and project files for new features

Brings render graph closer to AAA engine standards, enabling efficient memory usage, lower driver overhead, and a more flexible API.

Ghost.RenderGraph.Concept/RenderGraphContext.cs

@@ -75,6 +75,21 @@ internal sealed class MockCommandBuffer
     {
 #if DEBUG
         Console.WriteLine(nameof(AliasBarrier) + ": " + resourceBefore + " to " + resourceAfter);
+#endif
+    }
+
+    public void BeginRenderPass(int nativePassIndex, int colorAttachmentCount, bool hasDepth)
+    {
+#if DEBUG
+        Console.WriteLine($"\n=== BeginRenderPass (Native Pass {nativePassIndex}) ===");
+        Console.WriteLine($"  Color attachments: {colorAttachmentCount}, Depth: {hasDepth}");
+#endif
+    }
+
+    public void EndRenderPass()
+    {
+#if DEBUG
+        Console.WriteLine("=== EndRenderPass ===\n");
 #endif
     }
 }