Function default_store_path 

pub fn default_store_path(profile_dir: &Path) -> PathBuf

Where the persisted default store id is written, alongside the Chrome profile directory.

For the default layout this resolves to <platform_data_dir>/k-ruoka-mcp/default_store, a sibling of the profile/ sub-directory. For a custom K_RUOKA_PROFILE it is a sibling of that directory.