Function from_scheme_instances 

pub fn from_scheme_instances<'a, A, I, F>(
    instances: I,
    to_arg: F,
) -> ValueAssignment<A>
where
    A: Eq + Hash + Clone,
    I: IntoIterator<Item = (&'a SchemeInstance, &'a HashMap<String, String>)>,
    F: Fn(&SchemeInstance) -> A,

Extract value promotions from an iterator of instantiated schemes using the default catalog’s values-scheme name.

For each scheme instance:

• If instance.scheme_name == "Argument from Values" and a "value" binding is present, the scheme’s conclusion is mapped to the bound value.
• Otherwise, the scheme is skipped silently.

to_arg converts a SchemeInstance to the caller’s argument label type — typically by reading the conclusion literal. For encounter use this is a closure producing an ArgumentId from instance.conclusion.

Bindings are passed in separately because SchemeInstance does not retain its bindings post-instantiation — only the resolved literals. Callers must keep the original bindings alongside each instance.