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.DSL/ShaderParser/Model/ShaderModel.cs

@@ -0,0 +1,78 @@
+namespace Ghost.DSL.ShaderParser.Model;
+
+public class ShaderModel
+{
+    public string Name { get; set; } = string.Empty;
+    public PropertiesBlockModel? Properties { get; set; }
+    public PipelineBlockModel? Pipeline { get; set; }
+    public List<PassBlockModel> Passes { get; set; } = new();
+    public List<FunctionCallModel> FunctionCalls { get; set; } = new();
+}
+
+public class PropertiesBlockModel
+{
+    public List<PropertyDeclarationModel> Properties { get; set; } = new();
+}
+
+public class PropertyDeclarationModel
+{
+    public string? Scope { get; set; }
+    public string Type { get; set; } = string.Empty;
+    public string Name { get; set; } = string.Empty;
+    public List<string> Initializer { get; set; } = new();
+}
+
+public class PipelineBlockModel
+{
+    public Dictionary<string, string> Statements { get; set; } = new();
+}
+
+public class PassBlockModel
+{
+    public string Name { get; set; } = string.Empty;
+    public PipelineBlockModel? LocalPipeline { get; set; }
+    public DefinesBlockModel? Defines { get; set; }
+    public IncludesBlockModel? Includes { get; set; }
+    public KeywordsBlockModel? Keywords { get; set; }
+    public HlslBlockModel? Hlsl { get; set; }
+    public List<ShaderEntryModel> ShaderEntries { get; set; } = new();
+}
+
+public class DefinesBlockModel
+{
+    public List<string> Defines { get; set; } = new();
+}
+
+public class IncludesBlockModel
+{
+    public List<string> Includes { get; set; } = new();
+}
+
+public class KeywordsBlockModel
+{
+    public List<KeywordGroupModel> Groups { get; set; } = new();
+}
+
+public class KeywordGroupModel
+{
+    public string? Scope { get; set; }
+    public List<string> Keywords { get; set; } = new();
+}
+
+public class HlslBlockModel
+{
+    public string Code { get; set; } = string.Empty;
+}
+
+public class ShaderEntryModel
+{
+    public string EntryType { get; set; } = string.Empty;  // "mesh", "pixel", "task", etc.
+    public string ShaderPath { get; set; } = string.Empty;
+    public string EntryPoint { get; set; } = string.Empty;
+}
+
+public class FunctionCallModel
+{
+    public string Name { get; set; } = string.Empty;
+    public List<string> Arguments { get; set; } = new();
+}