refactor(client): separate accepted negotiation state from peer evidence

crates/irtt-client/src/session/mod.rs

@@ -2,4 +2,4 @@ pub(crate) mod machine;
 mod negotiation;
 
 pub(crate) use negotiation::negotiate_params;
-pub use negotiation::{NegotiatedParams, NegotiationRestriction};
+pub use negotiation::{AcceptedSessionParameters, NegotiationChange, NegotiationResult};