Fix false USDC-short error while waiting for a qualified option.

Use risk-sizing preview ask/qty (same as auto-convert) instead of monitor book ask.

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

backend/app/strategy/engine.py

@@ -17,7 +17,7 @@ from ..env_store import live_ready
 from .clock import can_open_new, window_key
 from .exits import check_expiry_close, check_exits, resolve_exit_target
 from .group import next_group_id
-from .open_capacity import assess_open_capacity, maybe_notify_funds_short
+from .open_capacity import maybe_notify_funds_short
 
 logger = logging.getLogger(__name__)
 
@@ -219,9 +219,12 @@ class StrategyEngine:
             last_error = None
         allow_open = can_open_new(skip_weekends=skip_weekends)
         try:
-            open_cap = assess_open_capacity(self.db)
+            # 以损定仓（尤其选约杠杆）：用预览名义+定仓卖一，勿用监控盘口贵卖一×账本名义虚高「需USDC」
+            from .auto_usdc import preview_capacity_for_convert
+
+            open_cap = preview_capacity_for_convert(self.db)
         except Exception:
-            logger.exception("assess_open_capacity failed")
+            logger.exception("preview_capacity_for_convert failed")
             open_cap = {
                 "perp_can_open": None,
                 "option_can_open": None,
@@ -1045,15 +1048,17 @@ class StrategyEngine:
                 return
         if pick is None:
             try:
-                from .open_capacity import assess_open_capacity, funds_gate_blocks
+                from .auto_usdc import preview_capacity_for_convert
+                from .open_capacity import funds_gate_blocks
 
-                cap = assess_open_capacity(self.db)
+                # 与自动兑 USDC 同一口径（选约杠杆用隐含卖一估需），避免无合格约时用盘口贵卖一误报缺 USDC
+                cap = preview_capacity_for_convert(self.db)
                 blocked, why = funds_gate_blocks(cap)
                 if blocked and 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"
+                            "无合格期权；且按拟定仓估算交易账户 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。"
                         ),