Improve registry backup safety and add optional backup skipping (#710)

Tests/Wait-ForKeyPress.Tests.ps1

@@ -0,0 +1,11 @@
+Describe 'Wait-ForKeyPress' {
+    It 'exits cleanly without prompting when Silent is enabled' {
+        $scriptPath = Join-Path $PSScriptRoot '..\Scripts\CLI\Wait-ForKeyPress.ps1'
+        $command = "function Stop-Transcript {}; `$global:Silent = `$true; . '$scriptPath'; Wait-ForKeyPress"
+        $encodedCommand = [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes($command))
+
+        & powershell.exe -NoProfile -EncodedCommand $encodedCommand
+
+        $LASTEXITCODE | Should -Be 0
+    }
+}