fix: Use getUserAccount().orders instead of non-existent getOpenOrders()

lib/trading/sync-helper.ts

@@ -29,13 +29,18 @@ async function discoverExistingOrders(symbol: string, marketIndex: number): Prom
     const driftService = getDriftService()
     const driftClient = driftService.getClient()
     
-    // Get all open orders for this user
-    const orders = driftClient.getOpenOrders()
+    // Get user account and extract orders
+    const userAccount = driftClient.getUserAccount()
+    if (!userAccount) {
+      console.log('⚠️ No user account found, cannot discover orders')
+      return {}
+    }
     
     // Filter for orders on this market that are reduce-only
-    const marketOrders = orders.filter(order => 
+    const marketOrders = userAccount.orders.filter((order: any) => 
       order.marketIndex === marketIndex && 
-      order.reduceOnly === true
+      order.reduceOnly === true &&
+      order.orderId && order.orderId !== 0
     )
     
     const signatures: any = {}