fix: name a folder or unreadable file in place

A folder or a file the user cannot read at a destination ended --check
and the install on a traceback from the hashing pool. --check now gives
the reason per file, and the install fails that file alone, before any
download for a folder.

install.ps1

@@ -11,7 +11,7 @@
 
     $ErrorActionPreference = "Stop"
     $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-    $defaultInstallSha256 = "6d8af0dbca6697ba71692e5e482c8a16d9e8b9896652fec722d9c84f23bba047"
+    $defaultInstallSha256 = "c361b511d9550b2115d918a0233115cd9f42920bce881f41395c3d7614be534d"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }