Refactor RenderGraph barrier/state tracking system

Major overhaul of resource barrier and state tracking in RenderGraph:
- Introduce ResourceBarrierData for explicit (layout, access, sync) tracking.
- Separate aliasing and transition barriers; explicit aliasing support.
- Remove BufferHint; infer buffer usage from BufferUsage flags.
- Update TextureAccess/BufferAccess to include usage requirements.
- Improve enums (BarrierSync, BarrierAccess, BarrierLayout) for D3D12 alignment.
- Update D3D12CommandBuffer to use new barrier data and error handling.
- Make D3D12DescriptorHeap a class; add ReleaseSampler to IResourceDatabase.
- Reset resource pools and aliasing managers each frame.
- Batch and flush barriers efficiently per pass.
- Update HLSL mesh shader macros to [NumThreads].
- Remove obsolete code and improve documentation.
This refactor improves correctness, extensibility, and prepares for advanced features.

Ghost.Graphics/RenderGraphModule/RenderGraphPass.cs

@@ -37,9 +37,6 @@ internal abstract class RenderGraphPassBase
     public readonly List<Identifier<RGResource>>[] resourceWrites = new List<Identifier<RGResource>>[(int)RenderGraphResourceType.Count];
     public readonly List<Identifier<RGResource>>[] resourceCreates = new List<Identifier<RGResource>>[(int)RenderGraphResourceType.Count];
 
-    // Buffer usage hints (maps buffer resource ID to hint)
-    public readonly Dictionary<int, BufferHint> bufferHints = new(8);
-
     // Execution state
     public bool culled;
     public bool hasSideEffects;
@@ -79,8 +76,6 @@ internal abstract class RenderGraphPassBase
             resourceCreates[i].Clear();
         }
 
-        bufferHints.Clear();
-
         culled = false;
         hasSideEffects = false;
     }