Preserve ledger venue provenance (#39)

* feat: preserve ledger venue provenance

* fix: satisfy ledger test lint ratchet

* fix: advance image migration inventory

tests/test_v1_portfolios_ledger.py

@@ -147,6 +147,97 @@ def test_ledger_trade_duplicate_same_payload() -> None:
     assert resp.json()["status"] == "duplicate"
 
 
+def test_ledger_trade_round_trips_and_forwards_venue_provenance() -> None:
+    settings = _make_settings()
+    repo = _make_service_repo(
+        trade=_make_trade(execution_venue="NXT", order_venue="SOR")
+    )
+    with _with_repo(repo):
+        client = _make_client(settings)
+        resp = client.post(
+            _NEW_PATH,
+            json=_trade_payload(execution_venue="NXT", order_venue="SOR"),
+            headers={"Authorization": "Bearer svc-token"},
+        )
+
+    assert resp.status_code == 201
+    assert resp.json()["execution_venue"] == "NXT"
+    assert resp.json()["order_venue"] == "SOR"
+    assert repo.insert_ledger_trade.call_args.kwargs["execution_venue"] == "NXT"
+    assert repo.insert_ledger_trade.call_args.kwargs["order_venue"] == "SOR"
+
+
+def test_ledger_trade_allows_unknown_actual_venue_with_sor_route() -> None:
+    settings = _make_settings()
+    repo = _make_service_repo(trade=_make_trade(execution_venue=None, order_venue="SOR"))
+    with _with_repo(repo):
+        client = _make_client(settings)
+        resp = client.post(
+            _NEW_PATH,
+            json=_trade_payload(execution_venue=None, order_venue="SOR"),
+            headers={"Authorization": "Bearer svc-token"},
+        )
+
+    assert resp.status_code == 201
+    assert resp.json()["execution_venue"] is None
+    assert resp.json()["order_venue"] == "SOR"
+
+
+def test_ledger_trade_rejects_sor_as_execution_venue() -> None:
+    settings = _make_settings()
+    repo = _make_service_repo()
+    with _with_repo(repo):
+        client = _make_client(settings)
+        resp = client.post(
+            _NEW_PATH,
+            json=_trade_payload(execution_venue="SOR", order_venue="SOR"),
+            headers={"Authorization": "Bearer svc-token"},
+        )
+
+    assert resp.status_code == 422
+    repo.insert_ledger_trade.assert_not_called()
+
+
+def test_ledger_trade_rejects_unknown_request_fields() -> None:
+    settings = _make_settings()
+    repo = _make_service_repo()
+    with _with_repo(repo):
+        client = _make_client(settings)
+        resp = client.post(
+            _NEW_PATH,
+            json=_trade_payload(broker_ordered_at="2026-05-01T09:59:59+09:00"),
+            headers={"Authorization": "Bearer svc-token"},
+        )
+
+    assert resp.status_code == 422
+    repo.insert_ledger_trade.assert_not_called()
+
+
+def test_ledger_trade_openapi_exposes_nullable_venue_enums() -> None:
+    settings = _make_settings()
+    repo = _make_service_repo()
+    with _with_repo(repo):
+        client = _make_client(settings)
+        response = client.get("/openapi.json")
+
+    assert response.status_code == 200
+    properties = response.json()["components"]["schemas"]["LedgerTradeRequest"][
+        "properties"
+    ]
+    execution_options = properties["execution_venue"]["anyOf"]
+    order_options = properties["order_venue"]["anyOf"]
+    assert {tuple(option.get("enum", ())) for option in execution_options} == {
+        (),
+        ("KRX", "NXT"),
+    }
+    assert {tuple(option.get("enum", ())) for option in order_options} == {
+        (),
+        ("KRX", "NXT", "SOR"),
+    }
+    assert {option.get("type") for option in execution_options} == {"string", "null"}
+    assert {option.get("type") for option in order_options} == {"string", "null"}
+
+
 # ---------------------------------------------------------------------------
 # AC-3: same key + different payload → 409
 # ---------------------------------------------------------------------------