Validate admin site/app-pool exist before attempting to stop them

Adds pre-flight checks for AdminSiteName/AdminAppPool at the top of
deploy-iis-remote-apply.ps1 (same pattern as the public site), so a
wrong name fails fast with a clear error instead of silently skipping
the stop and leaving files locked for the wipe.

scripts/deploy-iis-remote-apply.ps1

@@ -78,6 +78,14 @@ if(!(Get-Website -Name $SiteName -ErrorAction SilentlyContinue)){
 if(!(Test-Path ('IIS:\AppPools\' + $AppPool))){
   throw "App pool '$AppPool' does not exist yet. Create it once manually before running this deploy."
 }
+if(![string]::IsNullOrWhiteSpace($AdminSiteName)){
+  if(!(Get-Website -Name $AdminSiteName -ErrorAction SilentlyContinue)){
+    throw "IIS admin site '$AdminSiteName' does not exist yet. Create the site and app pool once manually before running this deploy."
+  }
+  if(![string]::IsNullOrWhiteSpace($AdminAppPool) -and !(Test-Path ('IIS:\AppPools\' + $AdminAppPool))){
+    throw "Admin app pool '$AdminAppPool' does not exist yet. Create it once manually before running this deploy."
+  }
+}
 
 Write-Host "Stopping IIS site $SiteName and app pool $AppPool"
 try { Stop-Website -Name $SiteName } catch { }
@@ -134,9 +142,6 @@ Set-ItemProperty ('IIS:\AppPools\' + $AppPool) -Name enable32BitAppOnWin64 -Valu
 # --- Admin site ---
 $adminPublicDir = Join-Path $RemoteDir 'public-admin'
 if(![string]::IsNullOrWhiteSpace($AdminSiteName) -and (Test-Path $adminPublicDir)){
-  if(!(Get-Website -Name $AdminSiteName -ErrorAction SilentlyContinue)){
-    throw "IIS admin site '$AdminSiteName' does not exist yet. Create the site and app pool once manually before running this deploy."
-  }
   Write-Host "Configuring admin site $AdminSiteName"
   if(![string]::IsNullOrWhiteSpace($AdminAppPool)){
     Set-ItemProperty ('IIS:\Sites\' + $AdminSiteName) -Name applicationPool -Value $AdminAppPool