The pre-activation log (now persisted) showed activate dying at its
profile operation: as the target user with no daemon in the chroot,
nix can't open the store db ("big-lock: Permission denied"). Run a
temporary nix-daemon inside the chroot and point activate at it via
NIX_REMOTE=daemon. HOME_MANAGER_BACKUP_EXT=bak makes file collisions
(e.g. a stray autogenerated hyprland.conf) move aside instead of
aborting. Verified in the chroot on a real installed disk: HM symlinks
land, collision backed up.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>