Function register_extra_boolean_plugins 

pub fn register_extra_boolean_plugins(names: HashSet<String>)

Register .rhai plugin names that are safe to treat as boolean/pure for rewrite purposes (i.e. loaded plugins whose signature() reports return_type: Bool and safe_for_rewrite/deterministic/idempotent: true — the @pure+@returns bool doc-tag combination). Must be called before the first optimizer pass of the run — later calls are no-ops.