Run historical updater completion in a fresh interpreter so cached imports
cannot revive retired dependency installers. Share Git and ZIP completion,
carry receipt and recovery state, and preserve child exit status.
Route plugin admission, binary acquisition, desktop launch and build paths
through PM. Replace redundant helpers and tests with real worker, package,
publication and launch checks. Keep the shipped compatibility surface fixed.
Targeted Python and desktop checks pass. Native update journeys and fresh
production image qualification remain pending. This is a checkpoint before
those acceptance runs.
53e6f001c7