A small wrapper to improve ergonomics around Iggy streams
Shared event vocabulary for the axess workspace and platform domains. The Event<P> envelope carries cross-cutting metadata (id, time, tenant, kind, subject, actor, trace context, status) while leaving the payload type-parameterised per domain. EventSink<P> is the trait every producer rides; concrete sinks include a no-op default and a LogAndSwallow wrapper for best-effort emission paths.