CI: add the C++ ATL component on the Windows runner (notifications plugin needs atlbase.h)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tool/setup_flutter_windows.ps1

@@ -13,3 +13,14 @@ Add-Content $env:GITHUB_PATH "$F\bin"
 & "$F\bin\flutter.bat" config --no-analytics | Out-Null
 & "$F\bin\flutter.bat" --version
 if ($LASTEXITCODE) { exit 1 }
+
+# flutter_local_notifications_windows includes atlbase.h: the Build Tools
+# need the C++ ATL component. Added once on the host (runs as SYSTEM).
+$Vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
+$Vs = & $Vswhere -products * -latest -property installationPath
+if (-not (Get-ChildItem "$Vs\VC\Tools\MSVC\*\atlmfc\include\atlbase.h" -ErrorAction SilentlyContinue)) {
+  Write-Host "adding the C++ ATL component to $Vs"
+  $p = Start-Process -Wait -PassThru "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\setup.exe" `
+    -ArgumentList "modify --installPath `"$Vs`" --add Microsoft.VisualStudio.Component.VC.ATL --quiet --norestart --nocache"
+  if ($p.ExitCode -notin 0, 3010) { Write-Host "ATL install failed: $($p.ExitCode)"; exit 1 }
+}