feat(update): add transactional external updater

scripts/build_exe.ps1

@@ -120,6 +120,18 @@ if ($LASTEXITCODE -ne 0) {
     throw "$(Decode-Utf8Base64 "UHlJbnN0YWxsZXIg5omT5YyF5aSx6LSl77yM6YCA5Ye656CB"): $LASTEXITCODE"
 }
 
+$updaterSpec = Join-Path $repoRoot "cmshopee-updater.spec"
+$updaterDist = Join-Path $repoRoot "dist\updater"
+$updaterWork = Join-Path $repoRoot "build\updater"
+& $pythonExe @pythonArgs -m PyInstaller --noconfirm --clean --distpath $updaterDist --workpath $updaterWork $updaterSpec
+if ($LASTEXITCODE -ne 0) {
+    throw "独立更新器打包失败，退出码: $LASTEXITCODE"
+}
+$updaterExe = Join-Path $updaterDist "cmshopee-updater.exe"
+if (-not (Test-Path -LiteralPath $updaterExe)) {
+    throw "独立更新器产物不存在: $updaterExe"
+}
+
 $distDir = Join-Path $repoRoot "dist\cmshopee"
 $exePath = Join-Path $distDir "cmshopee.exe"
 if (-not (Test-Path -LiteralPath $exePath)) {
@@ -164,6 +176,7 @@ foreach ($path in @($releaseDir, $portableZip, $releaseMetadata)) {
 
 New-Item -ItemType Directory -Force -Path $releaseDir | Out-Null
 Get-ChildItem -LiteralPath $distDir -Force | Copy-Item -Destination $releaseDir -Recurse -Force
+Copy-Item -LiteralPath $updaterExe -Destination (Join-Path $releaseDir "cmshopee-updater.exe") -Force
 Set-Content -LiteralPath (Join-Path $releaseDir "version.txt") -Value $appVersion -Encoding ascii -NoNewline
 
 $readme = @(