updates on the reverse logistics

constants/constants.go

@@ -140,6 +140,10 @@ const (
 	NextActionInwardAtHub   = "inward_at_hub"  // carry it to a base and hand it over
 	NextActionHandedToHub   = "handed_to_hub"  // already inwarded at the base — nothing left for this rider
 	NextActionNone          = "none"           // terminal (delivered, cancelled, returned)
+	// NextActionReturnToSender: the parcel is being returned (RTO) — carry it
+	// back to the sender's pickup point. Only emitted when
+	// MILER_RTO_FLOW_ENABLED=true (the deployed rider app does not know it yet).
+	NextActionReturnToSender = "return_to_sender"
 )
 
 // Payment Modes