dispatch abstract method
Dispatch a verb invocation. Returns any JSON-serialisable value (or a Future thereof) — the bridge JSON-encodes and hands back to the JS Promise. Throw to reject the promise.
args is the list passed by JS (host.fs.read(path) → [path]).
Atoms validate arity / types and throw ArgumentError for schema
violations so the JS caller gets a clean error message.
Implementation
Future<Object?> dispatch(String verb, List<Object?> args);