Use an absolute path for CompileShaders.cmd

[bghgary]

[Created by Copilot on behalf of @bghgary]

The shader build step names the script as a bare CompileShaders.cmd, which only resolves because Windows falls back to searching the current directory when looking up an executable. That fallback is disabled whenever NoDefaultCurrentDirectoryInExePath is present in the environment — its presence alone is enough, the value is irrelevant — so any hardened build or automation environment fails with Generating HLSL shaders... followed by no such file or directory.

WORKING_DIRECTORY already points at Src/Shaders, so naming the script by absolute path keeps the same intent without relying on current-directory lookup.

Verified on Windows with the Visual Studio 17 2022 generator, building the DirectXTK target:

	variable set	variable unset
before	fails: no such file or directory	builds
after	builds	builds

The shader step regenerated the .inc files in each passing case.

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[walbourn]

You could make the same change in two places for DirectXTex if you want:

https://github.com/microsoft/DirectXTex/

as well as DirectX Tool Kit for DX12:

https://github.com/microsoft/DirectXTK12/

[bghgary]

[Responded by Copilot on behalf of @bghgary]

You could make the same change in two places for DirectXTex if you want

Done: microsoft/DirectXTex#730 and microsoft/DirectXTK12#431.