Report whether the runtime can currently satisfy archetype, and how.
Report availability for every archetype the runtime can currently satisfy.
Resolve request.archetype to a handler, create or focus its window, and
deliver payload. Returns once the handler is resolved and the window
created; delivery MAY complete asynchronously.
OptionalonRegister for availability changes (a napplet installed/removed, or a default
handler changed). The service forwards each change to served napplets as an
intent.changed push. Returns an unsubscribe handle. Resolvers whose
catalog never changes at runtime MAY omit this.
Abstract intent resolver. Implementors own the installed-napplet catalog, archetype→handler resolution, the user's default-handler preference, the "open with…" chooser, window creation/focus, and payload delivery. The service translates wire envelopes into these calls and back.