[idd] serialize framebuffer copies on one queue

Replace the rotating D3D12 copy queues with two framebuffer-bound
recording slots on one physical COPY queue. Keep allocator, command
list, query range, callback state, and fence target independent per
slot.

Submit source waits, execution, and signaling on the shared timeline.
Track framebuffer ownership through completion and serialize LGMP
publication around the last successfully published frame.

idd/LGIdd/CInteropResource.h

@@ -59,8 +59,8 @@ class CInteropResource
 
     bool IsReady() { return m_ready; }
     bool Compare(const ComPtr<ID3D11Texture2D>& srcTex);
-    void Signal();
-    void Sync(CD3D12CommandQueue& queue);
+    bool Signal();
+    bool Sync(CD3D12CommandSlot& slot);
     void SetFullDamage();
     void SetDirtyRects(const RECT * dirtyRects, unsigned nbDirtyRects);