Refactor: variant-aware shader/material pipeline overhaul

Major architectural update to graphics/material/shader system:
- Introduced strongly-typed key structs (Key64/Key128) for passes, variants, and pipelines; removed legacy key types.
- Implemented robust hashing and key generation utilities for efficient variant and pipeline lookup/caching.
- Shader compiler now compiles/caches all keyword variants using new key system; includes handled as lists.
- Switched to push constant root signature for per-draw data; updated HLSL and C# codegen accordingly.
- Refactored Material, Shader, and Pass data structures for cache efficiency and variant support.
- Pipeline library and PSO management now use 128-bit keys and variant-specific caching.
- Replaced WorldNode with SceneNode in editor/scene graph; introduced ComponentManager for archetype/query management.
- Migrated math utilities to Misaki.HighPerformance.Mathematics; updated editor controls.
- Updated all HLSL and codegen for new buffer/push constant layouts and macros.
- Misc: project reference cleanup, D3D12 Work Graph support, doc updates, and code modernization.

Ghost.Core/Graphics/ShaderDescriptor.cs

@@ -30,7 +30,7 @@ public struct ShaderEntryPoint
 public struct KeywordsGroup
 {
     public KeywordSpace space;
-    public List<string>? keywords;
+    public List<string> keywords;
 }
 
 public interface IPassDescriptor
@@ -53,7 +53,7 @@ public struct PropertyDescriptor
     public object? defaultValue;
 }
 
-public class FullPassDescriptor : IPassDescriptor
+public class PassDescriptor : IPassDescriptor
 {
     public string uniqueIdentifier = string.Empty;
     public string name = string.Empty;
@@ -70,19 +70,9 @@ public class FullPassDescriptor : IPassDescriptor
     public string Name => name;
 }
 
-public class FallbackPassDescriptor : IPassDescriptor
-{
-    public string fallbackPassIdentifier = string.Empty;
-    public string name = string.Empty;
-
-    public string Identifier => fallbackPassIdentifier;
-    public string Name => name;
-}
-
 public class ShaderDescriptor
 {
     public string name = string.Empty;
-    public string? generatedCodePath;
     public uint cbufferSize;
     public List<PropertyDescriptor> globalProperties = new();
     public List<PropertyDescriptor> properties = new();