fix: name --offline when given, keep page budget

--offline given with the variable set is named as the option, and the
runs the screen starts get it only when the user gave it. The first
install page stays under its 400 words, the 3.8 runs skip only the
pack test that needs generate_pack.

install.ps1

@@ -11,7 +11,7 @@
 
     $ErrorActionPreference = "Stop"
     $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-    $defaultInstallSha256 = "c138739989d2ea32639c470f3af89d5038604b7fb446f08cc37659e139b76605"
+    $defaultInstallSha256 = "749d14547ad7a5504ff6ee4c62aca2ec710839174e149df77759c70d3e4fe951"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }