feat(payverse): JPY 결제 지원 추가 및 금액 포맷 규칙 적용

- ChargeService에 JPY 전용 자격 증명 주입(payverse.jpy-*)
  - payverseCharge/payverseWebhook/payverseVerify에 KRW/JPY/USD 3분기 적용
  - JPY 금액 정수화(FLOOR) 처리 및 공통 함수 computePayverseAmount 추가
  - 검증/체크리스트 문서 추가(docs/20260501_payverse-jpy-지원.md)

src/main/kotlin/kr/co/vividnext/sodalive/can/charge/ChargeService.kt

@@ -85,6 +85,13 @@ class ChargeService(
     @Value("\${payverse.usd-secret-key}")
     private val payverseUsdSecretKey: String,
 
+    @Value("\${payverse.jpy-mid}")
+    private val payverseJpyMid: String,
+    @Value("\${payverse.jpy-client-key}")
+    private val payverseJpyClientKey: String,
+    @Value("\${payverse.jpy-secret-key}")
+    private val payverseJpySecretKey: String,
+
     @Value("\${payverse.host}")
     private val payverseHost: String,
 
@@ -106,18 +113,18 @@ class ChargeService(
         return when (charge.payment?.status) {
             PaymentStatus.REQUEST -> {
                 // 성공 조건 검증
-                val mid = if (request.requestCurrency == "KRW") {
-                    payverseMid
-                } else {
-                    payverseUsdMid
+                val mid = when (request.requestCurrency) {
+                    "KRW" -> payverseMid
+                    "JPY" -> payverseJpyMid
+                    else -> payverseUsdMid
                 }
                 val expectedSign = DigestUtils.sha512Hex(
                     String.format(
                         "||%s||%s||%s||%s||%s||",
-                        if (request.requestCurrency == "KRW") {
-                            payverseSecretKey
-                        } else {
-                            payverseUsdSecretKey
+                        when (request.requestCurrency) {
+                            "KRW" -> payverseSecretKey
+                            "JPY" -> payverseJpySecretKey
+                            else -> payverseUsdSecretKey
                         },
                         mid,
                         request.orderId,
@@ -126,9 +133,8 @@ class ChargeService(
                     )
                 )
 
-                val isAmountMatch = request.requestAmount.compareTo(
-                    charge.payment!!.price
-                ) == 0
+                val expectedAmount = computePayverseAmount(charge.payment!!.price, request.requestCurrency)
+                val isAmountMatch = request.requestAmount.compareTo(expectedAmount) == 0
 
                 val isSuccess = request.resultStatus == "SUCCESS" &&
                     request.mid == mid &&
@@ -241,21 +247,20 @@ class ChargeService(
             ?: throw SodaException(messageKey = "can.charge.invalid_request_restart")
 
         val requestCurrency = can.currency
-        val isKrw = requestCurrency == "KRW"
-        val mid = if (isKrw) {
-            payverseMid
-        } else {
-            payverseUsdMid
+        val mid = when (requestCurrency) {
+            "KRW" -> payverseMid
+            "JPY" -> payverseJpyMid
+            else -> payverseUsdMid
         }
-        val clientKey = if (isKrw) {
-            payverseClientKey
-        } else {
-            payverseUsdClientKey
+        val clientKey = when (requestCurrency) {
+            "KRW" -> payverseClientKey
+            "JPY" -> payverseJpyClientKey
+            else -> payverseUsdClientKey
         }
-        val secretKey = if (isKrw) {
-            payverseSecretKey
-        } else {
-            payverseUsdSecretKey
+        val secretKey = when (requestCurrency) {
+            "KRW" -> payverseSecretKey
+            "JPY" -> payverseJpySecretKey
+            else -> payverseUsdSecretKey
         }
 
         val charge = Charge(can.can, can.rewardCan)
@@ -270,12 +275,7 @@ class ChargeService(
         val savedCharge = chargeRepository.save(charge)
 
         val chargeId = savedCharge.id!!
-        val amount = BigDecimal(
-            savedCharge.payment!!.price
-                .setScale(4, RoundingMode.HALF_UP)
-                .stripTrailingZeros()
-                .toPlainString()
-        )
+        val amount = computePayverseAmount(savedCharge.payment!!.price, requestCurrency)
         val reqDate = savedCharge.createdAt!!.format(DateTimeFormatter.ofPattern("yyyyMMddHHmmss"))
         val sign = DigestUtils.sha512Hex(
             String.format(
@@ -312,16 +312,16 @@ class ChargeService(
         val member = memberRepository.findByIdOrNull(memberId)
             ?: throw SodaException(messageKey = "common.error.bad_credentials")
 
-        val isKrw = charge.can?.currency == "KRW"
-        val mid = if (isKrw) {
-            payverseMid
-        } else {
-            payverseUsdMid
+        val currency = charge.can?.currency
+        val mid = when (currency) {
+            "KRW" -> payverseMid
+            "JPY" -> payverseJpyMid
+            else -> payverseUsdMid
         }
-        val clientKey = if (isKrw) {
-            payverseClientKey
-        } else {
-            payverseUsdClientKey
+        val clientKey = when (currency) {
+            "KRW" -> payverseClientKey
+            "JPY" -> payverseJpyClientKey
+            else -> payverseUsdClientKey
         }
 
         // 결제수단 확인
@@ -351,11 +351,12 @@ class ChargeService(
                     val verifyResponse = objectMapper.readValue(body, PayverseVerifyResponse::class.java)
 
                     val customerId = "${serverEnv}_user_${member.id!!}"
+                    val expectedAmount = computePayverseAmount(charge.can!!.price, charge.can!!.currency)
                     val isSuccess = verifyResponse.resultStatus == "SUCCESS" &&
                         verifyResponse.transactionStatus == "SUCCESS" &&
                         verifyResponse.orderId.toLongOrNull() == charge.id &&
                         verifyResponse.customerId == customerId &&
-                        verifyResponse.requestAmount.compareTo(charge.can!!.price) == 0
+                        verifyResponse.requestAmount.compareTo(expectedAmount) == 0
 
                     if (isSuccess) {
                         // verify 함수의 232~248 라인과 동일 처리
@@ -737,4 +738,16 @@ class ChargeService(
         }
         return messageSource.getMessage("can.charge.payment_method.card", langContext.lang)
     }
+
+    // Payverse 금액 포맷: 통화별 규칙 적용
+    private fun computePayverseAmount(price: BigDecimal, currency: String): BigDecimal {
+        val scaled = if (currency == "JPY") {
+            // JPY: 강제 정수화, 소수점 버림
+            price.setScale(0, RoundingMode.FLOOR)
+        } else {
+            // 그 외: 4자리까지 반올림 후 불필요 0 제거
+            price.setScale(4, RoundingMode.HALF_UP).stripTrailingZeros()
+        }
+        return BigDecimal(scaled.stripTrailingZeros().toPlainString())
+    }
 }