malkhut: standardized order types — FIX/CCXT-aligned, multi-exchange mapping

order_types.py: Five-layer taxonomy normalized to industry standards:
  Layer 1: Base types (FIX Tag 40) — MARKET, LIMIT
  Layer 2: Time-in-force (FIX Tag 59) — GTC, IOC, FOK, GTD
  Layer 3: Conditional/Trigger (FIX Tag 3/4+MIT) — STOP_MARKET, STOP_LIMIT,
    TRIGGER_MARKET, TRIGGER_LIMIT, TRAILING_STOP
  Layer 4: Instructions (FIX Tag 18) — POST_ONLY, REDUCE_ONLY, HIDDEN, ICEBERG
  Layer 5: Compound (exchange-specific) — OCO, TP_SL

Cross-exchange mapping: BingX ↔ Binance ↔ Bybit (from CCXT source code).
Standards: FIX 4.4 Tag 40/59/18, CCXT unified API, ISO 10383 (MIC).

Transferability: strategy PARAMETERS transfer. ORDER TYPE NAMES are
venue-specific but semantics identical (LIMIT = LIMIT everywhere).

14 tests. README updated with full mapping table and standards references.

MALKHUT/malkhut/tests/test_order_types.py

@@ -0,0 +1,83 @@
+"""
+Tests for standardized order types — FIX/CCXT-aligned, multi-exchange.
+"""
+import pytest
+from malkhut.training.order_types import (
+    BaseType, TimeInForce, ConditionalType, OrderInstruction, CompoundOrder,
+    EXCHANGE_ORDER_MAP, normalize_to_exchange, get_supported_types, is_type_available,
+)
+
+
+class TestOrderTypeEnums:
+    def test_base_types(self):
+        assert BaseType.MARKET.value == "market"
+        assert BaseType.LIMIT.value == "limit"
+
+    def test_time_in_force(self):
+        assert TimeInForce.GTC.value == "gtc"
+        assert TimeInForce.IOC.value == "ioc"
+        assert TimeInForce.FOK.value == "fok"
+
+    def test_conditional_types(self):
+        assert ConditionalType.STOP_MARKET.value == "stop_market"
+        assert ConditionalType.STOP_LIMIT.value == "stop_limit"
+        assert ConditionalType.TRAILING_STOP.value == "trailing_stop"
+
+    def test_instructions(self):
+        assert OrderInstruction.POST_ONLY.value == "post_only"
+        assert OrderInstruction.REDUCE_ONLY.value == "reduce_only"
+
+    def test_compound(self):
+        assert CompoundOrder.OCO.value == "oco"
+        assert CompoundOrder.TP_SL.value == "tp_sl"
+
+
+class TestExchangeMapping:
+    def test_binance_has_all_types(self):
+        types = get_supported_types("binance")
+        assert "limit" in types
+        assert "market" in types
+        assert "stop_market" in types
+        assert "post_only" in types
+
+    def test_bingx_has_all_types(self):
+        types = get_supported_types("bingx")
+        assert "limit" in types
+        assert "market" in types
+        assert "trigger_market" in types
+
+    def test_bybit_has_all_types(self):
+        types = get_supported_types("bybit")
+        assert "limit" in types
+        assert "market" in types
+        assert "stop_market" in types
+
+    def test_normalize_limit_all_exchanges(self):
+        """LIMIT should map to LIMIT on all exchanges."""
+        for ex in ["binance", "bingx", "bybit"]:
+            assert normalize_to_exchange("limit", ex) == "LIMIT"
+
+    def test_normalize_market_all_exchanges(self):
+        """MARKET should map to MARKET on all exchanges."""
+        for ex in ["binance", "bingx", "bybit"]:
+            assert normalize_to_exchange("market", ex) == "MARKET"
+
+    def test_normalize_post_only_varies(self):
+        """POST_ONLY maps differently across exchanges."""
+        assert normalize_to_exchange("post_only", "binance") == "LIMIT_MAKER"
+        assert normalize_to_exchange("post_only", "bingx") == "POST_ONLY"
+        assert normalize_to_exchange("post_only", "bybit") == "POST_ONLY"
+
+    def test_normalize_unknown_type(self):
+        assert normalize_to_exchange("invalid_type", "binance") is None
+
+    def test_is_type_available(self):
+        assert is_type_available("limit", "binance")
+        assert is_type_available("stop_market", "bingx")
+        assert not is_type_available("invalid", "binance")
+
+    def test_get_supported_types_unique(self):
+        """Each exchange should support at least 8 types."""
+        for ex in ["binance", "bingx", "bybit"]:
+            types = get_supported_types(ex)
+            assert len(types) >= 8