fix: dedup 4624 login alerts and log Skip/dedup reasons (1.2.18-SAC)

Co-authored-by: Cursor <cursoragent@cursor.com>

tools/Test-ScriptSyntax.ps1

@@ -0,0 +1,8 @@
+param([string]$Path = (Join-Path $PSScriptRoot '..\Login_Monitor.ps1'))
+$errs = $null
+[void][System.Management.Automation.Language.Parser]::ParseFile((Resolve-Path $Path), [ref]$null, [ref]$errs)
+if ($errs) {
+    $errs | ForEach-Object { $_.ToString() }
+    exit 1
+}
+Write-Output 'OK'