Survive Binance eapi 418/429 with cooldown, soft start, and no ticker raise.

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

backend/app/strategy/engine.py

@@ -230,8 +230,15 @@ class StrategyEngine:
             except asyncio.CancelledError:
                 raise
             except Exception as e:
+                err = str(e)
+                # 限流时勿刷屏；拉长休眠给 eapi 冷却
+                if "418" in err or "429" in err or "cooldown" in err.lower():
+                    logger.warning("strategy tick rate-limited: %s", err[:200])
+                    self._set_state(last_error="币安期权接口限流，稍后自动重试")
+                    await asyncio.sleep(15)
+                    continue
                 logger.exception("strategy tick failed")
-                self._set_state(last_error=str(e))
+                self._set_state(last_error=err)
             await asyncio.sleep(1)
 
     async def _tick_async(self) -> None: