trajectory

The rollout data model - one shape for all (multi-turn) rollouts.

Every rollout in the SDK - single- or multi-turn, RL or SDFT - is a :class:Trajectory: an ordered list of :class:Turn\s (each a prompt + a sampled completion with per-token logprobs) plus a scalar reward. Harbor's RolloutDetail (ATIF) is converted into this at the engine boundary (:func:evsys_sdk.training.harbor_engine.run_harbor_rollouts), so the rest of the SDK only ever sees Trajectory. The IS-loss data prep (:mod:evsys_sdk.training.data_processing) emits one Datum per turn.