feat(perception): seal detector replay evidence

tests/test_perception_architecture.py

@@ -49,6 +49,29 @@ def test_m4_baseline_cannot_silently_select_another_source(tmp_path: Path) -> No
         load_m4_baseline(path)
 
 
+@pytest.mark.parametrize(
+    ("section", "key", "value", "message"),
+    (
+        ("calibration", "valid_fov_mask_sha256", "0" * 64, "calibration"),
+        ("detector", "minimum_score", 0.51, "detector"),
+        ("rollback", "worker_node", "worker-007", "rollback"),
+    ),
+)
+def test_m4_baseline_cannot_silently_tune_frozen_execution_identity(
+    tmp_path: Path,
+    section: str,
+    key: str,
+    value: object,
+    message: str,
+) -> None:
+    document = json.loads(BASELINE_PATH.read_text("utf-8"))
+    document[section][key] = value
+    path = tmp_path / "baseline.json"
+    path.write_text(json.dumps(document), "utf-8")
+    with pytest.raises(BaselineContractError, match=message):
+        load_m4_baseline(path)
+
+
 def test_reuse_inventory_separates_primitives_from_historical_wrappers() -> None:
     document = validate_reuse_inventory(REUSE_PATH)
     assert document["rules"]["bulk_legacy_migration_required"] is False