Run OKX auto USDC convert before option pick when trading USDC is short.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/strategy/engine.py

@@ -807,9 +807,44 @@ class StrategyEngine:
             self._set_state(phase="open", last_error="有未平仓，禁止开下一组")
             return
 
+        # OKX：先按盘口刷新名义并检测 USDC；不够则交易账户市价兑换（不依赖已选中合格期权）
+        try:
+            from .auto_usdc import prepare_okx_trading_usdc
+
+            prep = prepare_okx_trading_usdc(self.db)
+            conv = prep.get("convert") or {}
+            if conv.get("acted"):
+                self._set_state(
+                    last_error=None,
+                    phase="wait_signal",
+                )
+                logger.info("auto_usdc prepared: %s", conv.get("detail"))
+            elif conv.get("ok") is False and "不足" in str(conv.get("detail") or ""):
+                # 保留资金提示，但仍继续尝试选约（可能只是冷却/短暂失败）
+                logger.warning("auto_usdc: %s", conv.get("detail"))
+        except Exception:
+            logger.exception("prepare OKX USDC failed")
+
         self._set_state(phase="wait_signal")
         pick = await get_session().pick_for_open_async()
         if pick is None:
+            # 若期权仍不可开且刚才未兑成功，把资金状态写进错误，便于排查「为何没自动兑」
+            try:
+                from .open_capacity import assess_open_capacity
+
+                cap = assess_open_capacity(self.db)
+                if cap.get("option_can_open") is False:
+                    self._set_state(
+                        phase="wait_funds",
+                        last_error=(
+                            "无合格期权；且交易账户 USDC 不够开仓"
+                            f"（需≈{cap.get('option_need_usdc')}U / 有{cap.get('option_have_usdc')}U）。"
+                            "系统会在冷却后自动市价兑 USDC。"
+                        ),
+                    )
+                    return
+            except Exception:
+                pass
             self._set_state(
                 last_error="无合格期权：需剩余时长、杠杆（及已开启的ATM偏差）同时满足"
             )
@@ -842,11 +877,11 @@ class StrategyEngine:
             self._set_state(phase="idle", last_error="以损定仓计算异常，暂不开仓")
             return
 
-        # OKX：交易账户 USDC 不够开期权时，市价 USDT→USDC（目标=所需×2）；够则跳过
+        # 选约后名义可能变化，再检一次 USDC（force 跳过冷却，避免刚选完仍差一截）
         try:
             from .auto_usdc import ensure_okx_trading_usdc
 
-            ensure_okx_trading_usdc(self.db)
+            ensure_okx_trading_usdc(self.db, force=True)
         except Exception:
             logger.exception("auto USDC top-up failed")