feat(apps): bootstrap-winget downloads + installs the App Installer online (LTSC lacks it)

windows/apps/bootstrap-winget.ps1

@@ -1,5 +1,68 @@
 #Requires -Version 5.1
-$ErrorActionPreference='SilentlyContinue'
-# Register the inbox App Installer if present, else nothing to do (offline image w/o it).
+# Provision winget (the App Installer) when absent. Windows IoT Enterprise LTSC
+# ships WITHOUT the inbox Microsoft.DesktopAppInstaller package, so re-registering
+# it is not enough - we download and install it (plus dependencies) online at apply
+# time. Best-effort and idempotent: exit 0 if winget ends up available, else 1.
+$ErrorActionPreference = 'SilentlyContinue'
+
+function Test-Winget {
+    return [bool](Get-Command winget -ErrorAction SilentlyContinue)
+}
+
+# Fast path 1: winget already on PATH.
+if (Test-Winget) { exit 0 }
+
+# Fast path 2: an inbox App Installer package is present - just re-register it.
 Get-AppxPackage -AllUsers Microsoft.DesktopAppInstaller |
-  ForEach-Object { Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml" }
+    ForEach-Object { Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml" }
+if (Test-Winget) { exit 0 }
+
+# Slow path: download + install the App Installer and its dependencies online.
+$temp        = $env:TEMP
+$bundlePath  = Join-Path $temp 'Microsoft.DesktopAppInstaller.msixbundle'
+$vclibsPath  = Join-Path $temp 'Microsoft.VCLibs.x64.14.00.Desktop.appx'
+$uixamlNupkg = Join-Path $temp 'microsoft.ui.xaml.2.8.6.nupkg'
+$uixamlExtract = Join-Path $temp 'uixaml.2.8.6'
+$uixamlAppx  = Join-Path $uixamlExtract 'tools\AppX\x64\Release\Microsoft.UI.Xaml.2.8.appx'
+
+$bundleUrl = 'https://aka.ms/getwinget'
+$vclibsUrl = 'https://aka.ms/Microsoft.VCLibs.x64.14.00.Desktop.appx'
+$uixamlUrl = 'https://globalcdn.nuget.org/packages/microsoft.ui.xaml.2.8.6.nupkg'
+
+function Get-File {
+    param([string]$Url, [string]$Destination)
+    try {
+        Invoke-WebRequest -Uri $Url -OutFile $Destination -UseBasicParsing
+        return (Test-Path $Destination)
+    } catch {
+        return $false
+    }
+}
+
+# Download the App Installer bundle (required).
+if (-not (Get-File -Url $bundleUrl -Destination $bundlePath)) { exit 1 }
+
+# Download the VCLibs desktop dependency (required).
+if (-not (Get-File -Url $vclibsUrl -Destination $vclibsPath)) { exit 1 }
+
+# Download the UI.Xaml 2.8 nuget package (a .zip) and extract the appx from it.
+if (-not (Get-File -Url $uixamlUrl -Destination $uixamlNupkg)) { exit 1 }
+try {
+    if (Test-Path $uixamlExtract) { Remove-Item -Path $uixamlExtract -Recurse -Force }
+    Add-Type -AssemblyName System.IO.Compression.FileSystem
+    [System.IO.Compression.ZipFile]::ExtractToDirectory($uixamlNupkg, $uixamlExtract)
+} catch {
+    exit 1
+}
+if (-not (Test-Path $uixamlAppx)) { exit 1 }
+
+# Install order: VCLibs dependency, then UI.Xaml dependency, then the bundle with
+# both supplied as DependencyPath. Per-user Add-AppxPackage (toolbox runs as the
+# real admin user at first logon).
+Add-AppxPackage -Path $vclibsPath
+Add-AppxPackage -Path $uixamlAppx
+Add-AppxPackage -Path $bundlePath -DependencyPath $vclibsPath, $uixamlAppx
+
+# Final re-check.
+if (Test-Winget) { exit 0 }
+exit 1