The required windows job moves from windows-2025 to ubuntu-latest, running
checksum-verified Windows Node under Wine at Linux-job wall clock (2m46s
warm vs 7-9min); master's serial-windows native-kernel reference is
untouched, and a new master-only wine-apt-cache job seeds the apt cache
every pull request restores. The experiment workflow folds into ci.yml,
the Agent Note moves to implemented with measured results, and the two CI
topology notes update to the shipped facts.
