[CanReader]

What this changes

Fixes so Debug builds compile and start on Windows with MSVC.

• Vector<T, N>::operator[] is now constexpr. Vector2D::GetX() and GetY() are constexpr and call it, so MSVC rejected them with C3615 in every file that includes Math/Vector.hpp. GCC and Clang accept it because they only complain when the function is actually used in a constant expression.

• DirectX11Renderer::Initialize() retries without D3D11_CREATE_DEVICE_DEBUG when device creation returns DXGI_ERROR_SDK_COMPONENT_MISSING. The debug layer comes from the Graphics Tools optional Windows feature, and without it a Debug build logged "Unable to initialize graphics!" and exited. It also logs the HRESULT now when creation fails.

• The downstream game job now replaces SleakCraft's Engine with a symlink to this checkout. SleakCraft#90 made Engine a submodule, so the job built against an empty folder and fails on every engine PR since.

Why

The Windows Debug build didn't compile, and once it did, -r d3d11 (the default on Windows) couldn't start on a machine without Graphics Tools. DX12 already copes with a missing debug layer.

This also covers the Windows part #224 left open: DX11 and DX12 reload and the Windows file watcher now work on Windows.

How it was verified

• Builds on Windows (MSVC 2022, Debug)
• Started on DX11, DX12, Vulkan and OpenGL on Windows without Graphics Tools installed
• Shader hot reload on Windows: edited flat_shader.hlsl while a world was running on DX11 and on DX12, and it reloaded both times
• Builds on Linux. Not rebuilt there; the Vector change is one keyword and the DX11 change only compiles on Windows.

Tested locally on top of Shader-HotReload, not on top of the current staging.

Goes with CanReader/SleakCraft fix/windows-debug-build, same branch name so its CI builds against this one.