Blazen Events

Defines the core event traits and built-in event types used for inter-component communication within the Blazen framework.

Every piece of data flowing between workflow steps is an [Event]. Events carry a stable string identifier ([Event::event_type]) used for routing, serialization, and cross-language boundaries.

The [AnyEvent] trait provides type-erased access so that the internal event queue can hold heterogeneous events without generics.