added seprate auditable in entity

src/main/java/com/billpaymentservice/bbps/entites/BillPayment.java

@@ -1,6 +1,5 @@
 package com.billpaymentservice.bbps.entites;
 
-import java.time.LocalDateTime;
 import java.util.List;
 
 import jakarta.persistence.CascadeType;
@@ -17,7 +16,7 @@ import lombok.Setter;
 @Setter
 @Entity
 @Table(name = "bill_payment")
-public class BillPayment {
+public class BillPayment extends Auditable {
 
     @Id
     @Column(name = "txn_id")
@@ -53,10 +52,7 @@ public class BillPayment {
     @Column(name = "customer_mobile")
     private String customerMobNo;
 
-    @Column(name = "created_at")
-    private LocalDateTime createdAt = LocalDateTime.now();
-
     // 🔗 One bill payment has many remitter identities
     @OneToMany(mappedBy = "billPayment", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
     private List<RemitterIdentity> remitterIdentities;
-}
+}