fix(windows): deploy-host reads build env from Machine scope

Reads PUNKTFUNK_NVENC_LIB_DIR/LIBCLANG_PATH/CMAKE_POLICY_VERSION_MINIMUM directly from
Machine scope into the process, so the build is correct even when the SSH/parent shell
predates setup-build-env.ps1 (env is inherited at spawn).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/windows/deploy-host.ps1

@@ -33,6 +33,14 @@ $vcvars = Find-VcVars
 Write-Host "vcvars : $vcvars"
 Set-Location $repo
 
+# Load the persisted build env (Machine scope) into THIS process, so the build sees it even
+# if this shell was started before setup-build-env.ps1 ran (env is inherited at spawn time).
+foreach ($k in 'PUNKTFUNK_NVENC_LIB_DIR','LIBCLANG_PATH','CMAKE_POLICY_VERSION_MINIMUM') {
+  $v = [Environment]::GetEnvironmentVariable($k, 'Machine')
+  if ($v) { [Environment]::SetEnvironmentVariable($k, $v, 'Process'); Write-Host "env    : $k=$v" }
+  else { Write-Warning "env $k not set (run setup-build-env.ps1)" }
+}
+
 # 1. stop the service so the .exe is writable
 Write-Host "stopping $svc ..."
 & sc.exe stop $svc | Out-Null