* fix(wsl-host): chat and text generation never run a Windows-side agent CLI on a WSL host
* fix(wsl-host): a Windows-only claude or codex reads as not installed to every CLI caller
* fix(wsl-host): say a Windows-only claude or codex is installed only on Windows at sign-in
* test(wsl): move the lane's chat envelope out of the contract to break an import cycle
* test(native-chat): inject guest mounts into the stock lookup the WSL guest-path tests exercise
