fix: correct PnL math and add health probe

app/api/health/route.ts

@@ -0,0 +1,16 @@
+import { NextResponse } from 'next/server'
+
+/**
+ * Health check endpoint for Docker HEALTHCHECK
+ * Returns 200 OK if the server is running
+ */
+export async function GET() {
+  return NextResponse.json(
+    { 
+      status: 'healthy',
+      timestamp: new Date().toISOString(),
+      uptime: process.uptime(),
+    },
+    { status: 200 }
+  )
+}

app/api/trading/execute/route.ts

@@ -240,9 +240,10 @@ export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTr
         // Save the closure to database
         try {
           const holdTimeSeconds = Math.floor((Date.now() - oppositePosition.entryTime) / 1000)
-          const profitPercent = ((closeResult.closePrice! - oppositePosition.entryPrice) / oppositePosition.entryPrice) * 100
-          const accountPnL = profitPercent * oppositePosition.leverage * (oppositePosition.direction === 'long' ? 1 : -1)
-          const realizedPnL = (oppositePosition.currentSize * accountPnL) / 100
+          const priceProfitPercent = oppositePosition.direction === 'long'
+            ? ((closeResult.closePrice! - oppositePosition.entryPrice) / oppositePosition.entryPrice) * 100
+            : ((oppositePosition.entryPrice - closeResult.closePrice!) / oppositePosition.entryPrice) * 100
+          const realizedPnL = closeResult.realizedPnL ?? (oppositePosition.currentSize * priceProfitPercent) / 100
           
           await updateTradeExit({
             positionId: oppositePosition.positionId,