Fix PriceResult slots serialization that broke open-group response.

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

backend/app/strategy/engine.py

@@ -82,7 +82,15 @@ class StrategyEngine:
             r = self.matcher.close_group(reason="emergency")
             if r.ok:
                 self._after_close()
-            return {"close": r.__dict__, "state": self.state()}
+            return {
+                "close": {
+                    "ok": r.ok,
+                    "detail": r.detail,
+                    "liquidity_wait": r.liquidity_wait,
+                    "data": r.data,
+                },
+                "state": self.state(),
+            }
 
     def _after_close(self) -> None:
         s = get_settings()
@@ -147,7 +155,7 @@ class StrategyEngine:
 
         # 有仓：盯平仓
         if pos.get("status") == "open":
-            self._set_state(phase="open")
+            self._set_state(phase="open", last_error=None)
             upl = self.matcher.unrealized()
             decision = check_exits(
                 perp_upl=float(upl["perp_upl"]),