WGL smoke tests

Manual bring-up tests for the Windows host layer (drop-in opengl32.dll). Both replicate the GLFW/LWJGL bootstrap Minecraft uses and verify a rendered triangle via glReadPixels; exit code 0 means pass.

wgl_smoke.cpp - hand-rolled Win32/WGL sequence (dummy context on a hidden helper window, ARB pixel format + 3.2 core forward-compatible context, gdi32 pixel-format forwarding, swap loop, readback).
glfw_smoke.cpp - the same flow driven by a real GLFW binary, which also exercises GLFW's zero-area helper window (the case that needs the DirectVulkan no-swapchain-at-init path).

Build (x64 Native Tools prompt), with GLFW binaries for the second test:

cl /nologo /EHsc /W3 wgl_smoke.cpp user32.lib gdi32.lib
cl /nologo /EHsc /W3 glfw_smoke.cpp /I%GLFW%\include %GLFW%\lib-vc2022\glfw3dll.lib user32.lib gdi32.lib

Run with the MobileGL opengl32.dll copy (and glfw3.dll, plus ANGLE's libEGL.dll/libGLESv2.dll/d3dcompiler_47.dll for DirectGLES) in the exe directory:

set MOBILEGL_BACKEND_TYPE=DirectVulkan   (or DirectGLES)
set MOBILEGL_LOG_FILE_PATH=smoke.log
wgl_smoke.exe && glfw_smoke.exe