feat(graphics): refactor pipeline keying and allocators

Major refactor of graphics pipeline keying, shader cache, and resource allocation.
Replaced most Allocator usage with AllocationHandle, modernized logger usage,
and unified pipeline state keys. Updated MeshUtility to use AllocationHandle.FreeList.
Added new shader pipeline architecture docs and improved error handling throughout.

BREAKING CHANGE: Pipeline keying and resource allocation APIs have changed.

src/Runtime/Ghost.Graphics.D3D12/Utilities/D3D12Utility.cs

@@ -53,9 +53,9 @@ internal static unsafe class D3D12Utility
         var ptr = uPtr.Get();
         if (ptr != null)
         {
-            Debug.Assert(ptr != other);
+            Logger.DebugAssert(ptr != other);
             var refCount = ptr->Release();
-            Debug.Assert(refCount == 0);
+            Logger.DebugAssert(refCount == 0);
         }
 
         uPtr = new UniquePtr<T>(other);
@@ -69,7 +69,7 @@ internal static unsafe class D3D12Utility
         if (ptr != null)
         {
             var refCount = ptr->Release();
-            //Debug.Assert(refCount == 0);
+            //Logger.DebugAssert(refCount == 0);
         }
     }