SSDP can only be tried on a machine that shares the printers' network
segment, and the development container is a router hop away. This builds
the existing discover_printers example as a Windows .exe and uploads it as
a CI artifact, with a README for whoever runs it and a SHA-256 file.
Uses the windows-latest self-hosted runner continuum-cad already uses
(Windows PowerShell 5.1, MSVC present, upload-artifact@v3 only). The proxy
links OpenSSL directly and Windows has none, so the job builds it with
vcpkg (x64-windows-static-md, linked into the .exe) in a directory of its
own, away from the CAD pipeline's. The job smoke-runs the exe, then runs
the discovery tests on Windows after the upload, so a Windows-only test
failure turns the job red without withholding the executable.
Not run anywhere yet: this container cannot build for Windows (no MSVC or
mingw). The first CI run is the first real build.
