Add llm-first tuning proposal policy

src/aituner/cli.py

@@ -288,6 +288,7 @@ def cmd_study_tune(args: argparse.Namespace) -> int:
     capability_profile = load_capability_profile(study, study_spec_path=spec_path)
     proposal_files = [Path(item).resolve() for item in (args.proposal_file or [])]
     max_trials = args.max_trials or (len(proposal_files) if proposal_files else 2)
+    proposal_policy = args.proposal_policy
     if max_trials <= 0:
         raise SpecError("max_trials must be positive")
     if proposal_files and max_trials > len(proposal_files):
@@ -387,7 +388,7 @@ def cmd_study_tune(args: argparse.Namespace) -> int:
             else:
                 guided_proposal = (
                     build_harness_guided_proposal(harness_context)
-                    if harness_context is not None
+                    if harness_context is not None and proposal_policy == "harness-first"
                     else None
                 )
                 if guided_proposal is not None:
@@ -782,6 +783,15 @@ def build_parser() -> argparse.ArgumentParser:
     tune.add_argument("--store-root")
     tune.add_argument("--proposal-file", action="append")
     tune.add_argument("--max-trials", type=int)
+    tune.add_argument(
+        "--proposal-policy",
+        choices=("harness-first", "llm-first"),
+        default="harness-first",
+        help=(
+            "Choose whether deterministic harness proposals are tried before the LLM "
+            "or whether the LLM proposes directly from the harness prompt/context."
+        ),
+    )
     tune.add_argument(
         "--skip-baseline",
         action="store_true",