Add --comment option to predict, recorded in YAML sidecar

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_cli_predict.py

@@ -103,6 +103,25 @@ def test_ref_yaml_contains_expected_fields(tmp_path):
     assert data["dataset"] == str(dataset)
     assert data["checkpoint"] == str(checkpoint.resolve())
     assert "timestamp" in data
+    assert "comment" not in data
+
+
+def test_ref_yaml_includes_comment_when_provided(tmp_path):
+    ckpt_dir = tmp_path / "checkpoints"
+    ckpt_dir.mkdir()
+    checkpoint = ckpt_dir / "best.pt"
+    checkpoint.touch()
+
+    out = tmp_path / "pred.parquet"
+    dataset = tmp_path / "full.manifest"
+    pred_uuid = str(uuid.uuid4())
+
+    ref_path = _write_prediction_ref(
+        checkpoint, pred_uuid, out, dataset, comment="baseline sweep run 3"
+    )
+    data = yaml.safe_load(ref_path.read_text())
+
+    assert data["comment"] == "baseline sweep run 3"
 
 
 def test_ref_timestamp_is_iso_format(tmp_path):