malkhut(wire): OrderType as three orthogonal dimensions — Fable's corrections

CRITICAL REFACTOR based on Fable's review (S9 roadmap item):

Before: flat enum conflating order types with TIF/instructions
  OrderType had MARKET, LIMIT, IOC, FOK, POST_ONLY, REDUCE_ONLY, etc.

After: three orthogonal dimensions (FIX-aligned):
  1. OrderType (Tag 40): what the order IS
     LIMIT, MARKET, STOP_MARKET, STOP_LIMIT, TRIGGER_MARKET, TRIGGER_LIMIT,
     TRAILING_STOP, OCO, TP_SL
  2. TimeInForce (Tag 59): how long it LIVES
     GTC, IOC, FOK, GTD
  3. Instructions (Tag 18): behavioral modifiers
     POST_ONLY, REDUCE_ONLY, HIDDEN, ICEBERG

Key corrections:
- POST_ONLY is an instruction on a LIMIT order, not a standalone type
- IOC/FOK are TimeInForce values, not order types
- BingX trailing_stop -> native TRAILING_STOP_MARKET (not TRIGGER_MARKET)
- FulfilmentAction.time_in_force: new field, default GTC

Exchange mappings restructured:
  EXCHANGE_ORDER_TYPE_MAP: OrderType -> exchange native 'type' param
  EXCHANGE_TIF_MAP: TimeInForce -> exchange native 'timeInForce' param
  EXCHANGE_INSTRUCTION_MAP: Instruction -> exchange encoding

21 files changed. 380+ tests pass. Backward compatible.

MALKHUT/malkhut/actions.py

@@ -11,6 +11,16 @@ from typing import Any, Mapping, Optional, Tuple
 
 from malkhut.state import ActionKind, AgentRole, OrderType, Side
 
+# Lazy import to avoid circular dependency (training -> actions -> training)
+_TimeInForce = None
+
+def _get_TimeInForce():
+    global _TimeInForce
+    if _TimeInForce is None:
+        from malkhut.training.order_types import TimeInForce
+        _TimeInForce = TimeInForce
+    return _TimeInForce
+
 
 @dataclass(frozen=True, slots=True)
 class FulfilmentAction:
@@ -24,8 +34,14 @@ class FulfilmentAction:
     cancel_order_id: Optional[str] = None
     reduce_only: bool = False
     post_only: bool = False
+    time_in_force: str = "GTC"
     metadata: Mapping[str, Any] = field(default_factory=dict)
 
+    @property
+    def time_in_force_enum(self):
+        TIF = _get_TimeInForce()
+        return TIF(self.time_in_force)
+
 
 @dataclass(frozen=True, slots=True)
 class CounterpartyAction: