Today a non-didbot user sets VIBESCROBBLE_AS in Claude Code's settings env. A userConfig field in plugin.json would ask for it in /plugin at install or enable time (2.1.83+), and hooks receive it as CLAUDE_PLUGIN_OPTION_<KEY>.
${user_config.X} is refused in shell-form hooks since 2.1.207, so hook.py reads the variable. vibescrobble statusline and post do not see plugin options, so the hook would have to pass the value on, as it does the session's DID.