feat(V2): IBKR simple write tools (place/amend/cancel/close)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/unit/exchanges/ibkr/test_tools.py

@@ -45,3 +45,44 @@ async def test_get_tick_uses_cache_or_subscribes():
     )
     assert res["last_price"] == 99.5
     ws.subscribe_tick.assert_awaited_once_with(42)
+
+
+@pytest.mark.asyncio
+async def test_place_order_enforces_leverage():
+    client = MagicMock()
+    client.get_account = AsyncMock(return_value={
+        "netliquidation": {"amount": 10000},
+    })
+    client.place_order = AsyncMock(return_value={"order_id": "O1"})
+    creds = {"max_leverage": 2}
+    res = await t.place_order(
+        client, t.PlaceOrderReq(symbol="AAPL", side="buy", qty=10),
+        creds=creds, last_price=100.0,
+    )
+    assert res["order_id"] == "O1"
+
+
+@pytest.mark.asyncio
+async def test_cancel_order_calls_client():
+    client = MagicMock()
+    client.cancel_order = AsyncMock(return_value={"order_id": "O1", "canceled": True})
+    res = await t.cancel_order(client, t.CancelOrderReq(order_id="O1"))
+    assert res["canceled"] is True
+
+
+@pytest.mark.asyncio
+async def test_place_order_rejects_excessive_leverage():
+    from fastapi import HTTPException
+    client = MagicMock()
+    client.get_account = AsyncMock(return_value={
+        "netliquidation": {"amount": 1000},
+    })
+    creds = {"max_leverage": 2}
+    # Order notional = 100*100 = 10000 vs equity 1000 → ratio 10x >> 2x cap → 403
+    with pytest.raises(HTTPException) as exc_info:
+        await t.place_order(
+            client, t.PlaceOrderReq(symbol="AAPL", side="buy", qty=100),
+            creds=creds, last_price=100.0,
+        )
+    assert exc_info.value.status_code == 403
+    assert exc_info.value.detail["error"] == "LEVERAGE_CAP_EXCEEDED"