- load_vars_file() now supports force parameter to override existing variables
- App Defaults uses force=yes to properly apply saved user preferences
- Added safety check for SSH_KEYS_FILE in install_ssh_keys_into_ct()
- Initialize ENABLE_GPU, ENABLE_NESTING, ENABLE_KEYCTL, ENABLE_MKNOD, PROTECT_CT, CT_TIMEZONE in base_settings()
- Added fallback defaults in echo_default() to prevent unbound variable errors when advanced_settings is skipped