feat: add integration test infra and bootstrapper updates

test/integration/packer/scripts/compact.ps1

@@ -0,0 +1,25 @@
+# Zero out free space so the resulting .box file is small.
+#
+# Runs last, just before Packer initiates shutdown. Cleans caches and the WU
+# component store, which directly shrinks the on-disk footprint of the VHDX.
+# We intentionally do not call `cipher /w:C:\` here: it costs 15–30 minutes
+# and its only payoff is better tarball compression of unused space, which
+# only matters when shipping the box. Re-add it before publishing publicly.
+
+$ErrorActionPreference = 'Continue'
+
+# Clean Windows Update download cache and component store.
+Stop-Service -Name wuauserv -Force -ErrorAction SilentlyContinue
+Remove-Item  -Path "$env:WINDIR\SoftwareDistribution\Download\*" -Recurse -Force -ErrorAction SilentlyContinue
+& dism /Online /Cleanup-Image /StartComponentCleanup /ResetBase /Quiet
+
+# Empty Recycle Bin and temp dirs.
+Get-ChildItem -Path "$env:TEMP" -Force -ErrorAction SilentlyContinue |
+  Remove-Item -Recurse -Force -ErrorAction SilentlyContinue
+Clear-RecycleBin -Force -ErrorAction SilentlyContinue
+
+# Light defrag pass to consolidate free extents. Quick on an SSD-backed VHDX.
+& defrag C: /U /V
+
+# Drop hibernation file (Windows 11 has it on by default).
+& powercfg /h off