feat: add comprehensive Windows PowerShell script usage instructions

- Enhanced ScriptPreview with detailed Windows-specific installation steps including execution policy handling and winget availability checks
- Added localization support for all script preview UI elements and Windows usage instructions
- Improved script generator with automatic unblocking, admin privilege warnings, and winget validation

src/lib/scriptGenerator.ts

@@ -140,6 +140,28 @@ function generateWindowsScript(packages: SelectedPackage[]): string {
 
 Write-Host "Starting package installation for Windows..."
 
+# Try to unblock this script (no-op if not needed)
+try { Unblock-File -Path $MyInvocation.MyCommand.Path -ErrorAction SilentlyContinue } catch {}
+
+# Warn if not running as Administrator (some installs may require elevation)
+$isAdmin = ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
+if (-not $isAdmin) {
+    Write-Warning "It's recommended to run this script as Administrator for best results."
+}
+
+# Ensure winget is available
+if (-not (Get-Command winget -ErrorAction SilentlyContinue)) {
+    Write-Warning "Windows Package Manager (winget) is not installed."
+    Write-Host "We'll open the Microsoft Store page for 'App Installer' (includes winget)."
+    Write-Host "After installation completes, please re-run this script."
+    try {
+        Start-Process "ms-windows-store://pdp/?productId=9NBLGGH4NNS1"
+    } catch {
+        Write-Host "If the Store didn't open, install 'App Installer' manually from: https://aka.ms/getwinget"
+    }
+    exit 1
+}
+
 # Install packages using winget
 Write-Host "Installing packages: ${packageNames}"