Type Alias ConstellationInitHandler 

pub type ConstellationInitHandler = fn(constellations_root: PathBuf, name: String, scope_note: Option<String>, atlases: Vec<PathBuf>, json: bool) -> Pin<Box<dyn Future<Output = ()> + Send>>;

v0.82: Constellation-level handlers. Mirror the Atlas pattern one layer up. The binary registers handlers that call into the vela-constellation crate.