Refactor: add command allocator & render target strategies

Major refactor of graphics infrastructure:
- Introduce ICommandAllocator and D3D12CommandAllocator for explicit command buffer management.
- Change ICommandBuffer.Begin to require an allocator.
- Add IRenderTargetStrategy abstraction with swap chain and texture implementations.
- Update IRenderer to use RenderTargetStrategy instead of direct handle.
- Add DPI scaling support to swap chains (ScaleX/ScaleY, SetScale).
- RenderSystem now supports thread-safe swap chain resize requests.
- Remove persistent copy command buffer; use per-frame allocators.
- Make Logger public/static and clean up API visibility.
- Update .editorconfig and debug layer enablement.
These changes improve modularity, DPI-awareness, and future extensibility.

.editorconfig

@@ -2,6 +2,7 @@
 csharp_new_line_before_open_brace = all
 csharp_preserve_single_line_statements = true
 csharp_preserve_single_line_blocks = true
+csharp_style_prefer_primary_constructors = false
 dotnet_sort_system_directives_first = false
 dotnet_separate_import_directive_groups = false
 max_line_length = 400