Replaces the stale "not yet implemented" note for installer.sh
autostart with the actual mechanism (dracut's official
20-apply-live-updates.sh pre-pivot hook via a top-level /updates/
directory, not squashfs/EROFS remastering - that image is EROFS
despite the filename, and hit a reproducible erofs-utils extraction
bug even freshly built from source). Adds the milestone entry for the
first clean end-to-end run through every module, live in Proxmox.
