mentra v0.8.0

mentra v0.8.0

Mentra v0.8.0 adds two small, additive runtime controls for per-phase agent
tiering: changing reasoning options mid-session, and stopping a run gracefully
without discarding the work it gathered.

Highlights

Per-phase reasoning options

• Add Agent::set_reasoning(Option<ReasoningOptions>) and the session wrapper
  Session::set_reasoning(...), mirroring set_model: a stateful override threaded
  into every subsequent model request and persisted with the agent record.
• This makes a per-phase reasoning split expressible on a single agent — for
  example, run the gather rounds at a low effort, then raise the effort (and,
  together with set_model, switch to a stronger model) for a final synthesis turn
  — without re-spawning the agent and losing the gathered context.

Graceful run stop

• Add RunOptions::stop, a graceful-stop signal distinct from cancellation. The
  runner checks it at each round boundary, where the transcript is at a consistent
  point. When it is tripped the run ends successfully, committing the gathered
  transcript, instead of returning Cancelled and rolling the run back.
• Use it to stop a run once enough has been gathered while keeping the gathered
  context available for a follow-up turn on the same agent. cancellation still
  aborts-and-rolls-back as before; stop is the keep-the-work variant.

Compatibility

• Both additions are additive. RunOptions gains one field (stop), defaulting to
  None; constructions that use ..RunOptions::default() are unaffected.

Crate Versions

• mentra 0.8.0
• mentra-provider 0.3.0 remains unchanged and does not need to be republished.

Verification

This release is expected to pass:

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace