Enable serial-windows to execute the complete check:ci on the in-house
self-hosted Windows pool instead of the disabled hosted windows-2025
lane. Point the job at [self-hosted, dsh-win-ci, windows] and wire it
into all-checks-passed so it gates pull requests.
The Wine-emulated windows job remains the required win32 signal for
PRs that cannot reach the self-hosted pool; this lane adds a real
native-Windows run where one is available.