Add high-performance material/shader system (Ghost.Shader.Concept)

Introduces a new Ghost.Shader.Concept project implementing a modern, data-oriented material and shader system with:
- Global/local keyword bitsets (fast O(1) ops, 64 bytes)
- Multi-pass shader program and per-pass render state overrides
- Thread-safe, 16-byte aligned material property blocks
- Material pooling to reduce GC pressure
- Batch renderer for efficient PSO grouping and async variant warmup
- Full demo (Program.cs) and extensive documentation (ARCHITECTURE.md, README.md, PROJECT_SUMMARY.md)
- Minor integration: new enums, doc updates, and keyword handling in existing code

No breaking changes to the existing engine; all new code is isolated. This serves as a reference implementation for high-performance, extensible material/shader architectures.

Ghost.Graphics/RHI/Common.cs

@@ -58,7 +58,7 @@ public readonly struct ShaderPassKey : IEquatable<ShaderPassKey>
 
 public readonly struct GraphicsPipelineKey
 {
-    public const int KEY_STRING_LENGTH = 17; // 16 chars + null terminator
+    public const int KEY_STRING_LENGTH = 33; // 32 chars + null terminator
 
     public readonly UInt128 value;
 
@@ -98,12 +98,13 @@ public readonly struct GraphicsPipelineKey
 
     public Result GetString(Span<char> destination)
     {
-        if (!value.TryFormat(destination, out _, "X16"))
+        if (!value.TryFormat(destination, out var num, "X16"))
         {
             return Result.Failure("Failed to format GraphicsPipelineKey to string.");
         }
 
-        destination[16] = '\0';
+        // Just in case.
+        destination[num] = '\0';
         return Result.Success();
     }
 
@@ -733,7 +734,7 @@ public struct BufferDesc
     }
 
     /// <summary>
-    /// Memory type for the buffer
+    /// Memory space for the buffer
     /// </summary>
     public ResourceMemoryType MemoryType
     {
@@ -814,7 +815,7 @@ public struct SwapChainDesc
 public struct SwapChainTarget
 {
     /// <summary>
-    /// Target type
+    /// Target space
     /// </summary>
     public SwapChainTargetType Type
     {

Ghost.Graphics/RHI/ICommandBuffer.cs

@@ -11,7 +11,7 @@ namespace Ghost.Graphics.RHI;
 public interface ICommandBuffer : IDisposable
 {
     /// <summary>
-    /// Gets the type of the command buffer.
+    /// Gets the space of the command buffer.
     /// </summary>
     CommandBufferType Type
     {
@@ -125,7 +125,7 @@ public interface ICommandBuffer : IDisposable
     /// Binds an index buffer for indexed drawing.
     /// </summary>
     /// <param name="buffer">The handle to the graphics buffer containing index data.</param>
-    /// <param name="type">The type of indices (e.g., 16-bit or 32-bit).</param>
+    /// <param name="type">The space of indices (e.g., 16-bit or 32-bit).</param>
     /// <param name="offset">The offset in bytes from the start of the buffer.</param>
     void SetIndexBuffer(Handle<GraphicsBuffer> buffer, IndexType type, ulong offset = 0);
 
@@ -179,9 +179,9 @@ public interface ICommandBuffer : IDisposable
     /// <summary>
     /// Uploads the specified data to the buffer represented by the given handle.
     /// </summary>
-    /// <typeparam name="T">The unmanaged Value type of the elements to upload to the buffer.</typeparam>
+    /// <typeparam name="T">The unmanaged Value space of the elements to upload to the buffer.</typeparam>
     /// <param name="buffer">A handle to the buffer that will receive the uploaded data.</param>
-    /// <param name="data">A read-only span containing the data to upload to the buffer. The span must contain elements of type
+    /// <param name="data">A read-only span containing the data to upload to the buffer. The span must contain elements of space
     /// <typeparamref name="T"/>.</param>
     void UploadBuffer<T>(Handle<GraphicsBuffer> buffer, ReadOnlySpan<T> data)
         where T : unmanaged;

Ghost.Graphics/RHI/IGraphicsEngine.cs

@@ -50,10 +50,10 @@ public interface IGraphicsEngine : IDisposable
     void ClearRenderers();
 
     /// <summary>
-    /// Creates a new command allocator for the specified command buffer type.
+    /// Creates a new command allocator for the specified command buffer space.
     /// </summary>
-    /// <param name="type">The type of command buffer for which to create the allocator. The default is CommandBufferType.Graphics.</param>
-    /// <returns>An <see cref="ICommandAllocator"/> instance configured for the specified command buffer type.</returns>
+    /// <param name="type">The space of command buffer for which to create the allocator. The default is CommandBufferType.Graphics.</param>
+    /// <returns>An <see cref="ICommandAllocator"/> instance configured for the specified command buffer space.</returns>
     ICommandAllocator CreateCommandAllocator(CommandBufferType type = CommandBufferType.Graphics);
 
     /// <summary>

Ghost.Graphics/RHI/IPipelineLibrary.cs

@@ -6,7 +6,7 @@ namespace Ghost.Graphics.RHI;
 public interface IShaderPipeline
 {
     /// <summary>
-    /// Pipeline type
+    /// Pipeline space
     /// </summary>
     PipelineType Type
     {

Ghost.Graphics/RHI/IResourceDatabase.cs

@@ -20,7 +20,7 @@ public interface IResourceDatabase : IDisposable
     /// <summary>
     /// Imports an external unmanaged resource and returns a handle for use within the resource management system.
     /// </summary>
-    /// <typeparam name="T">The type of the unmanaged resource pointer to import.</typeparam>
+    /// <typeparam name="T">The space of the unmanaged resource pointer to import.</typeparam>
     /// <param name="resourcePtr">A pointer to the external unmanaged resource to be imported. Must remain valid for the duration of the resource's usage.</param>
     /// <param name="initialState">The initial state to assign to the imported resource.</param>
     /// <returns>A handle representing the imported resource, which can be used for subsequent operations.</returns>