AgentSessionProjection and the schemas nested in it reuse pebble's types
through with_replacement; the AgentSession prefix marks the projection's
own types where fabro already has a schema of that name, and pebble's
event-level types keep their names. The round-trip test builds a
projection over a scripted stream, validates it against the spec with the
spec as the root document, checks every serialized key is declared, and
validates every enum variant this build knows. The TypeScript client is
regenerated.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>