A consistent view of an Omni.Session at a point in time.

Returned by Omni.Session.get_snapshot/1 and Omni.Session.subscribe/1,2.

Fields:

• :id — the session's identifier
• :title — the session's human-friendly title, or nil
• :tree — the %Omni.Session.Tree{} of committed conversation history at the snapshot instant
• :agent — an %Omni.Agent.Snapshot{} capturing the wrapped agent's state, in-flight pending messages, and currently-streaming partial message

To compose the complete view of everything the session knows right now:

committed = Omni.Session.Tree.messages(snapshot.tree)
in_flight = snapshot.agent.pending ++ List.wrap(snapshot.agent.partial)
committed ++ in_flight

snapshot.agent.state.messages mirrors Tree.messages(snapshot.tree) — treat the tree as the source of truth for committed structure; agent.pending / agent.partial carry the streaming tail.