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/pnl.ts

@@ -0,0 +1,16 @@
+import type { PositionSnapshot } from "./strategy";
+
+export function computePositionPnl(
+  position: PositionSnapshot,
+  bestBid?: number | null,
+  bestAsk?: number | null
+): number {
+  const priceForPnl = position.positionAmt > 0 ? bestBid : bestAsk;
+  if (!Number.isFinite(priceForPnl as number)) return 0;
+  const absAmt = Math.abs(position.positionAmt);
+  return position.positionAmt > 0
+    ? ((priceForPnl as number) - position.entryPrice) * absAmt
+    : (position.entryPrice - (priceForPnl as number)) * absAmt;
+}
+
+