Interface MilanoContextSource

Supplies and updates context values. Milano validates each change atomically; an invalid update is rejected whole and reported. subscribe returns a cancellation, invoked by the runtime at teardown so a source never retains callbacks for views that are gone.

interface MilanoContextSource {
    current: Readonly<Record<string, MilanoValue>>;
    subscribe(
        onUpdate: (values: Readonly<Record<string, MilanoValue>>) => void,
    ): () => void;
}