Strip the unused .input(z.object({ lastEventId })) from all 6 subscription
procedures — the parameter was never consumed by eventBusIterable. Remove the
now-unused zod import. Add at-most-once delivery JSDoc to the EventBus interface
to make the real guarantee explicit. Add compliance comment above
onConversationUpdate noting what to wire when a conversation view is built.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>