Fix P&L calculation and signal flip detection

- Fix external closure P&L using tp1Hit flag instead of currentSize
- Add direction change detection to prevent false TP1 on signal flips
- Signal flips now recorded with accurate P&L as 'manual' exits
- Add retry logic with exponential backoff for Solana RPC rate limits
- Create /api/trading/cancel-orders endpoint for manual cleanup
- Improves data integrity for win/loss statistics

app/api/trading/cancel-orders/route.ts

@@ -0,0 +1,51 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { cancelAllOrders } from '@/lib/drift/orders'
+import { initializeDriftService } from '@/lib/drift/client'
+
+/**
+ * Cancel all orders for a symbol
+ * POST /api/trading/cancel-orders
+ */
+export async function POST(request: NextRequest) {
+  try {
+    const body = await request.json()
+    const { symbol } = body
+
+    if (!symbol) {
+      return NextResponse.json(
+        { success: false, error: 'Symbol required' },
+        { status: 400 }
+      )
+    }
+
+    console.log(`🗑️ Manual order cancellation requested for ${symbol}`)
+
+    // Initialize Drift service
+    await initializeDriftService()
+
+    // Cancel all orders
+    const result = await cancelAllOrders(symbol)
+
+    if (result.success) {
+      return NextResponse.json({
+        success: true,
+        message: `Cancelled ${result.cancelledCount || 0} orders for ${symbol}`,
+        cancelledCount: result.cancelledCount,
+      })
+    } else {
+      return NextResponse.json(
+        { success: false, error: result.error },
+        { status: 500 }
+      )
+    }
+  } catch (error) {
+    console.error('❌ Error cancelling orders:', error)
+    return NextResponse.json(
+      {
+        success: false,
+        error: error instanceof Error ? error.message : 'Failed to cancel orders',
+      },
+      { status: 500 }
+    )
+  }
+}