chore: import upstream snapshot with attribution

.github/scripts/verify_windows_install.ps1

@@ -0,0 +1,64 @@
+param(
+    [Parameter(Mandatory = $true)][string]$ArtifactExePath,
+    [Parameter(Mandatory = $true)][string]$Version
+)
+
+$ErrorActionPreference = 'Stop'
+Set-StrictMode -Version Latest
+
+$repoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
+$resolvedArtifact = (Resolve-Path -LiteralPath $ArtifactExePath).Path
+$tempRoot = Join-Path $env:RUNNER_TEMP ("jcode-windows-install-verify-" + [guid]::NewGuid().ToString('N'))
+$localAppData = Join-Path $tempRoot 'localappdata'
+$appData = Join-Path $tempRoot 'appdata'
+$userProfile = Join-Path $tempRoot 'userprofile'
+$jcodeHome = Join-Path $tempRoot '.jcode'
+$installDir = Join-Path $localAppData 'jcode\bin'
+
+New-Item -ItemType Directory -Force -Path $localAppData, $appData, $userProfile, $jcodeHome | Out-Null
+
+$env:LOCALAPPDATA = $localAppData
+$env:APPDATA = $appData
+$env:USERPROFILE = $userProfile
+$env:JCODE_HOME = $jcodeHome
+
+$installScript = Join-Path $repoRoot 'scripts\install.ps1'
+
+& $installScript `
+    -InstallDir $installDir `
+    -Version $Version `
+    -ArtifactExePath $resolvedArtifact `
+    -SkipAlacrittySetup `
+    -SkipHotkeySetup
+
+$launcherPath = Join-Path $installDir 'jcode.exe'
+$versionDir = Join-Path $localAppData ('jcode\builds\versions\' + $Version.TrimStart('v') + '\jcode.exe')
+$stablePath = Join-Path $localAppData 'jcode\builds\stable\jcode.exe'
+
+foreach ($path in @($launcherPath, $versionDir, $stablePath)) {
+    if (-not (Test-Path -LiteralPath $path)) {
+        throw "Expected installed file missing: $path"
+    }
+}
+
+$versionOutput = & $launcherPath --version
+if ($LASTEXITCODE -ne 0) {
+    throw "Installed launcher failed to run --version"
+}
+
+if ($versionOutput -notmatch 'jcode') {
+    throw "Installed launcher returned unexpected version output: $versionOutput"
+}
+
+& $installScript `
+    -InstallDir $installDir `
+    -Version $Version `
+    -ArtifactExePath $resolvedArtifact `
+    -SkipAlacrittySetup `
+    -SkipHotkeySetup
+
+if (-not (Test-Path -LiteralPath $launcherPath)) {
+    throw "Launcher missing after reinstall: $launcherPath"
+}
+
+Write-Host "Windows install verification passed for $Version" -ForegroundColor Green