Fix multi-sample manifest aggregation

backend/tests/test_sprint178_mol_operational_pack.py

@@ -97,6 +97,7 @@ def test_real_data_matrix_propagates_project_region_and_persisted_area() -> None
     assert 'REAL_AREA_NAME="${sample_slug} AOI"' in multi
     assert 'project_region="Mol, Kempen"' in multi
     assert 'REAL_PROJECT_REGION="${project_region}"' in multi
+    assert 'manifest_path = Path(sys.argv[3])' in multi
 
 
 def test_mol_operational_runner_uses_real_positive_qa_and_background_paths() -> None:

scripts/run_multi_sample_detection_quality_matrix.sh

@@ -167,7 +167,7 @@ from pathlib import Path
 
 output_dir = Path(sys.argv[1])
 base_url = sys.argv[2]
-manifest_path = sys.argv[3]
+manifest_path = Path(sys.argv[3])
 manifest_payload = json.loads(manifest_path.read_text(encoding="utf-8-sig"))
 manifest_samples = {
     str(sample.get("sample_slug") or "").lower(): sample