feat(V2): IBKR complex order payload builders (bracket/OCO/OTO)

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

tests/unit/exchanges/ibkr/test_orders_complex.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from cerbero_mcp.exchanges.ibkr.orders_complex import (
+    OrderSpec,
+    build_bracket_payload,
+    build_oco_payload,
+)
+
+
+def test_bracket_three_legs_with_oca():
+    payload = build_bracket_payload(
+        conid=42, sec_type="STK", side="BUY", qty=10,
+        entry_price=150.0, stop_loss=145.0, take_profit=160.0,
+        tif="GTC", exchange="SMART",
+    )
+    assert "orders" in payload
+    legs = payload["orders"]
+    assert len(legs) == 3
+    oca = legs[0].get("ocaGroup")
+    assert oca and all(l.get("ocaGroup") == oca for l in legs[1:])
+    assert legs[0]["orderType"] == "LMT"
+    assert legs[0]["price"] == 150.0
+    assert legs[0]["side"] == "BUY"
+    assert legs[1]["side"] == "SELL"
+    assert legs[2]["side"] == "SELL"
+    assert legs[1]["orderType"] == "STP"
+    assert legs[1]["auxPrice"] == 145.0
+    assert legs[2]["orderType"] == "LMT"
+    assert legs[2]["price"] == 160.0
+
+
+def test_oco_oca_group_and_type():
+    legs = [
+        OrderSpec(conid=1, sec_type="STK", side="BUY", qty=1,
+                  order_type="LMT", price=100),
+        OrderSpec(conid=1, sec_type="STK", side="BUY", qty=1,
+                  order_type="LMT", price=110),
+    ]
+    payload = build_oco_payload(legs)
+    assert len(payload["orders"]) == 2
+    oca = payload["orders"][0]["ocaGroup"]
+    for o in payload["orders"]:
+        assert o["ocaGroup"] == oca
+        assert o["ocaType"] == 1