fix(evidence): preserve legacy formula migration boundaries

harness/tests/test_evidence_formula_migration.py

@@ -24,3 +24,21 @@ def test_reviewed_formula_migration_has_deterministic_provenance_hash():
     assert second is not None
     assert first.provenance.source_sha256 == second.provenance.source_sha256
     assert first.provenance.source_sha256.startswith("sha256:")
+
+
+def test_incompatible_reviewed_legacy_formula_fails_closed_with_the_original_record():
+    formula = ConceptFormula(
+        concept="ablazione",
+        columns=["testo"],
+        sql="SELECT 2",
+        status="reviewed",
+        sources=["legacy manual"],
+    )
+
+    outcome = formula_store.legacy_formula_to_curated(
+        formula, legacy_path="formulas/ablazione-2.sql.md",
+    )
+
+    assert outcome.code == "legacy_formula_requires_manual_review"
+    assert outcome.legacy_path == "formulas/ablazione-2.sql.md"
+    assert outcome.formula == formula