fix(update): normalize windows.ps1 to LF and keep fixture here-string braces off column 0

The cherry-pick landed the file with CRLF endings and a fixture
here-string whose col-0 brace prematurely terminated the handoff test's
SelfTest-block strip, tripping the drive-python-not-the-shim guard on
fixture code. LF restored (matching main), child-script loop inlined.

scripts/desktop-update/windows.ps1

@@ -1247,10 +1247,7 @@ exit 0
 param([int]$Hold, [string]$ProgressLog)
 Write-Output "silent but logging"
 [Console]::Out.Flush()
-for ($i = 0; $i -lt $Hold; $i++) {
-    Add-Content -LiteralPath $ProgressLog -Value ("build tick {0}" -f $i)
-    Start-Sleep -Seconds 1
-}
+for ($i = 0; $i -lt $Hold; $i++) { Add-Content -LiteralPath $ProgressLog -Value ("build tick {0}" -f $i); Start-Sleep -Seconds 1 }
 exit 3
 '@
     [System.IO.File]::WriteAllText($childPs1, $childSource)