refactor: PaymentEntityV2에 orderId 필드 추가 및 취소 상태 변경 메서드 추가

src/main/kotlin/roomescape/payment/infrastructure/persistence/v2/PaymentEntityV2.kt

@@ -17,6 +17,7 @@ class PaymentEntityV2(
 
     val reservationId: Long,
     val paymentKey: String,
+    val orderId: String,
     val totalAmount: Int,
     val requestedAt: OffsetDateTime,
     val approvedAt: OffsetDateTime,
@@ -28,5 +29,10 @@ class PaymentEntityV2(
     val method: PaymentMethod,
 
     @Enumerated(EnumType.STRING)
-    val status: PaymentStatus
-) : PersistableBaseEntity(id)
+    var status: PaymentStatus
+) : PersistableBaseEntity(id) {
+
+    fun cancel() {
+        this.status = PaymentStatus.CANCELED
+    }
+}