Refactor render graph & DSL; remove material system

- Major optimization of Ghost.RenderGraph.Concept: pooled resources, zero-allocation hot paths, explicit queue types, and batch barrier APIs.
- Migrated Ghost.DSL shader compiler to ANTLR4-based parser; removed hand-written parser, added grammar files and semantic model conversion.
- Added CollectionPool/ListPool for pooled list management.
- Updated documentation for new architecture and performance.
- Removed Ghost.Shader.Concept (material/material system) from repo and solution.
- README.md replaced with a brief project statement.

Ghost.RenderGraph.Concept/RenderGraphPass.cs

@@ -1,50 +1,111 @@
+using System;
+using System.Collections.Generic;
+
 namespace Ghost.RenderGraph.Concept;
 
+public enum RenderQueueType
+{
+    Graphics,
+    Compute,
+    AsyncCompute,
+    Copy
+}
+
 internal abstract class RenderGraphPass
 {
-    public string Name { get; }
-    public int Index { get; }
-    public List<(RenderGraphResourceHandle handle, ResourceState state)> ResourceAccesses { get; }
+    public string Name { get; set; } = string.Empty;
+    public int Index { get; set; }
+    public RenderQueueType QueueType { get; set; }
+    public List<(RenderGraphResourceHandle handle, ResourceState state)> ResourceAccesses { get; set; }
     public List<int> Dependencies { get; } = new();
     public int RefCount { get; set; } = 0;
-    public bool AllowCulling { get; }
+    public bool AllowCulling { get; set; }
 
     protected RenderGraphPass(
         string name,
         int index,
+        RenderQueueType queueType,
         List<(RenderGraphResourceHandle handle, ResourceState state)> resourceAccesses,
         bool allowCulling)
     {
         Name = name;
         Index = index;
+        QueueType = queueType;
         ResourceAccesses = resourceAccesses;
         AllowCulling = allowCulling;
     }
 
+    protected void InitializeBase(
+        string name,
+        int index,
+        RenderQueueType queueType,
+        List<(RenderGraphResourceHandle handle, ResourceState state)> resourceAccesses,
+        bool allowCulling)
+    {
+        Name = name;
+        Index = index;
+        QueueType = queueType;
+        ResourceAccesses = resourceAccesses;
+        AllowCulling = allowCulling;
+        Dependencies.Clear();
+        RefCount = 0;
+    }
+
     public abstract void Execute(ICommandBuffer commandBuffer);
+    public abstract void Release();
+}
+
+internal static class RenderGraphPassPool<TPassData>
+    where TPassData : class
+{
+    public static readonly Stack<RenderGraphPass<TPassData>> Pool = new();
 }
 
 internal class RenderGraphPass<TPassData> : RenderGraphPass
     where TPassData : class
 {
-    public TPassData PassData { get; }
-    public Action<TPassData, ICommandBuffer> RenderFunc { get; }
+    public TPassData PassData { get; private set; }
+    public Action<TPassData, ICommandBuffer> RenderFunc { get; private set; }
 
     public RenderGraphPass(
         string name,
         int index,
+        RenderQueueType queueType,
         TPassData passData,
         Action<TPassData, ICommandBuffer> renderFunc,
         List<(RenderGraphResourceHandle handle, ResourceState state)> resourceAccesses,
         bool allowCulling)
-        : base(name, index, resourceAccesses, allowCulling)
+        : base(name, index, queueType, resourceAccesses, allowCulling)
     {
         PassData = passData;
         RenderFunc = renderFunc;
     }
 
+    public void Initialize(
+        string name,
+        int index,
+        RenderQueueType queueType,
+        TPassData passData,
+        Action<TPassData, ICommandBuffer> renderFunc,
+        List<(RenderGraphResourceHandle handle, ResourceState state)> resourceAccesses,
+        bool allowCulling)
+    {
+        InitializeBase(name, index, queueType, resourceAccesses, allowCulling);
+        PassData = passData;
+        RenderFunc = renderFunc;
+    }
+
     public override void Execute(ICommandBuffer commandBuffer)
     {
         RenderFunc(PassData, commandBuffer);
     }
+
+    public override void Release()
+    {
+        PassData = null!;
+        RenderFunc = null!;
+        // ResourceAccesses list ownership is transferred back to RenderGraph
+        ResourceAccesses = null!; 
+        RenderGraphPassPool<TPassData>.Pool.Push(this);
+    }
 }