更新 MakerEngine、OffsetMakerEngine 和 TrendEngine，重构订单同步逻辑，优化撤单和止损判断，新增订单计划生成和安全撤单功能，提升代码可读性和维护性。

src/utils/price.ts

@@ -0,0 +1,19 @@
+import type { AsterDepth, AsterTicker } from "../exchanges/types";
+
+export function getTopPrices(depth?: AsterDepth | null): { topBid: number | null; topAsk: number | null } {
+  const bid = Number(depth?.bids?.[0]?.[0]);
+  const ask = Number(depth?.asks?.[0]?.[0]);
+  return {
+    topBid: Number.isFinite(bid) ? bid : null,
+    topAsk: Number.isFinite(ask) ? ask : null,
+  };
+}
+
+export function getMidOrLast(depth?: AsterDepth | null, ticker?: AsterTicker | null): number | null {
+  const { topBid, topAsk } = getTopPrices(depth);
+  if (topBid != null && topAsk != null) return (topBid + topAsk) / 2;
+  const last = Number(ticker?.lastPrice);
+  return Number.isFinite(last) ? last : null;
+}
+
+