fix: pass the installer's own lint gate

install.py held a local it never read and, since the registry path
rules, a loop variable shadowing the platform module, so the py38
ruff gate the installer is held to failed. Both are fixed, and the
suite reads the two rules from the syntax tree since CI has no ruff.

install.ps1

@@ -8,7 +8,7 @@ param(
 
 $ErrorActionPreference = "Stop"
 $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-$defaultInstallSha256 = "dc6b428278a4352923c19ddcf055fd994aac1df77f35cb1d097e8f4c5d887ae1"
+$defaultInstallSha256 = "973e116ab59e233cd4fe5ebb77d4973bc06013b22b6388e80d12fa1d61fb0c73"
 $maximumInstallerBytes = 2MB
 $installerExit = 0
 $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }