critical: Cancel ghost orders after external closures

- Added order cancellation to Position Manager's external closure handler
- When on-chain SL/TP orders close position, remaining orders now cancelled automatically
- Prevents ghost orders from triggering unintended positions
- Real incident: Nov 20 SHORT stop-out left 32 ghost orders on Drift
- Risk: Ghost TP1 at $140.66 could fill later, creating unwanted LONG position
- Fix: Import cancelAllOrders() and call after trade removed from monitoring
- Non-blocking: Logs errors but doesn't fail trade closure if cancellation fails
- Files: lib/trading/position-manager.ts (external closure handler ~line 920)
- Documented as Common Pitfall #56

lib/trading/position-manager.ts

@@ -924,6 +924,23 @@ export class PositionManager {
         console.log(`🗑️ Removed trade ${tradeId} from monitoring (BEFORE DB update to prevent duplicates)`)
         console.log(`   Active trades remaining: ${this.activeTrades.size}`)
         
+        // CRITICAL: Cancel all remaining orders for this position (ghost order cleanup)
+        // When position closes externally (on-chain SL/TP), TP/SL orders may remain active
+        // These ghost orders can trigger unintended positions if price moves to those levels
+        console.log(`🗑️ Cancelling remaining orders for ${trade.symbol}...`)
+        try {
+          const { cancelAllOrders } = await import('../drift/orders')
+          const cancelResult = await cancelAllOrders(trade.symbol)
+          if (cancelResult.success) {
+            console.log(`✅ Cancelled ${cancelResult.cancelledCount || 0} ghost orders`)
+          } else {
+            console.error(`⚠️ Failed to cancel orders: ${cancelResult.error}`)
+          }
+        } catch (cancelError) {
+          console.error('❌ Error cancelling ghost orders:', cancelError)
+          // Don't fail the trade closure if order cancellation fails
+        }
+        
         try {
           await updateTradeExit({
             positionId: trade.positionId,