- add ensure_user_dir/ensure_user_file helpers in lib/core/base.sh, including
sudo-aware ownership correction under the invoking user’s home
- use the helpers across clean/optimize/purge/uninstall/whitelist to create
cache and export files safely (no naked mkdir/touch), including log files and
dry-run exports
- ensure purge stats/count files and update message caches are pre-created with
safe permissions
- add Darwin version helpers and skip LaunchServices/dyld rebuild on macOS 15+,
keeping the existing corruption protection for earlier versions
- guard brew cache timestamp writes and TCC permission flags with safe file
creation to avoid root-owned artifacts
