Add harness-guided tuning prompts

src/aituner/cli.py

@@ -146,6 +146,19 @@ def cmd_study_tune(args: argparse.Namespace) -> int:
         raw_proposal_path.write_text(proposal_text, encoding="utf-8")
         proposal = parse_proposal_text(proposal_text, study)
         store.write_proposal(study.study_id, proposal_name, proposal)
+        if proposal.should_stop:
+            executed.append(
+                {
+                    "trial_id": None,
+                    "proposal_name": proposal_name,
+                    "proposal_source": str(proposal_source) if proposal_source else "llm",
+                    "stopped": True,
+                    "diagnosis": proposal.diagnosis,
+                    "state_best_trial_id": state.best_trial_id,
+                    "state_best_request_rate": state.best_request_rate,
+                }
+            )
+            break
         trial, _ = store.materialize_trial(study=study, state=state, proposal=proposal)
         trial_spec_path = Path(trial.artifact_dir) / "trial_spec.json"
         result = run_trial(trial_spec_path)