feat: add windows helper scripts

scripts/windows/helper.ps1

@@ -0,0 +1,26 @@
+Set-StrictMode -Version Latest
+$ErrorActionPreference = "Stop"
+
+$ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+Import-Module (Join-Path $ScriptDir "VpnProxy.Windows.psm1") -Force
+
+try {
+  $raw = [Console]::In.ReadToEnd()
+  if ([string]::IsNullOrWhiteSpace($raw)) {
+    throw "Missing JSON input"
+  }
+
+  $request = $raw | ConvertFrom-Json
+  $payload = if ($request.PSObject.Properties.Name -contains "payload") { $request.payload } else { @{} }
+  $result = Invoke-VpnProxyAction -Action ([string]$request.action) -Payload $payload
+  $result | ConvertTo-Json -Depth 30 -Compress
+  exit 0
+} catch {
+  $errorResult = [ordered]@{
+    success = $false
+    action = "error"
+    error = $_.Exception.Message
+  }
+  $errorResult | ConvertTo-Json -Depth 10 -Compress
+  exit 1
+}