feat(character-image): 이미지 단독 구매 API 및 결제 연동 추가

- 구매 요청/응답 DTO 추가
- 미보유 시 캔 차감 및 구매 이력 저장
- 서명 URL(5분) 반환

src/main/kotlin/kr/co/vividnext/sodalive/can/payment/CanPaymentService.kt

@@ -13,6 +13,7 @@ import kr.co.vividnext.sodalive.can.use.UseCanCalculate
 import kr.co.vividnext.sodalive.can.use.UseCanCalculateRepository
 import kr.co.vividnext.sodalive.can.use.UseCanCalculateStatus
 import kr.co.vividnext.sodalive.can.use.UseCanRepository
+import kr.co.vividnext.sodalive.chat.character.image.CharacterImage
 import kr.co.vividnext.sodalive.common.SodaException
 import kr.co.vividnext.sodalive.content.AudioContent
 import kr.co.vividnext.sodalive.content.order.Order
@@ -327,4 +328,49 @@ class CanPaymentService(
             chargeRepository.save(charge)
         }
     }
+
+    @Transactional
+    fun spendCanForCharacterImage(
+        memberId: Long,
+        needCan: Int,
+        image: CharacterImage,
+        container: String
+    ) {
+        val member = memberRepository.findByIdOrNull(id = memberId)
+            ?: throw SodaException("잘못된 요청입니다.\n다시 시도해 주세요.")
+
+        val useRewardCan = spendRewardCan(member, needCan, container)
+        val useChargeCan = if (needCan - useRewardCan.total > 0) {
+            spendChargeCan(member, needCan = needCan - useRewardCan.total, container = container)
+        } else {
+            null
+        }
+
+        if (needCan - useRewardCan.total - (useChargeCan?.total ?: 0) > 0) {
+            throw SodaException(
+                "${needCan - useRewardCan.total - (useChargeCan?.total ?: 0)} " +
+                    "캔이 부족합니다. 충전 후 이용해 주세요."
+            )
+        }
+
+        if (!useRewardCan.verify() || useChargeCan?.verify() == false) {
+            throw SodaException("잘못된 요청입니다.\n다시 시도해 주세요.")
+        }
+
+        val useCan = UseCan(
+            canUsage = CanUsage.CHARACTER_IMAGE_PURCHASE,
+            can = useChargeCan?.total ?: 0,
+            rewardCan = useRewardCan.total,
+            isSecret = false
+        )
+        useCan.member = member
+        useCan.characterImage = image
+
+        useCanRepository.save(useCan)
+
+        setUseCanCalculate(null, useRewardCan, useChargeCan, useCan, paymentGateway = PaymentGateway.PG)
+        setUseCanCalculate(null, useRewardCan, useChargeCan, useCan, paymentGateway = PaymentGateway.POINT_CLICK_AD)
+        setUseCanCalculate(null, useRewardCan, useChargeCan, useCan, paymentGateway = PaymentGateway.GOOGLE_IAP)
+        setUseCanCalculate(null, useRewardCan, useChargeCan, useCan, paymentGateway = PaymentGateway.APPLE_IAP)
+    }
 }