feat(account): 대출 계좌 loan_amount/loan_rate/loan_method/loan_months/loan_start 필드 추가

- wallet 테이블: loan_amount(실행금액), loan_rate(연이자율%), loan_method(상환방식),
  loan_months(기간), loan_start(시작일) ALTER TABLE 추가
- Wallet 도메인/DTO/Mapper/Service 동기화
- WalletResponse.from()에 대출 필드 반영

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/main/java/com/sb/web/account/domain/Wallet.java

@@ -6,6 +6,7 @@ import lombok.Data;
 import lombok.NoArgsConstructor;
 
 import java.io.Serializable;
+import java.math.BigDecimal;
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 
@@ -29,6 +30,11 @@ public class Wallet implements Serializable {
     private Long openingBalance;  // 초기 잔액(부호있음: 자산+, 부채-)
     private LocalDate openingDate;
     private Long currentValue;    // 현재 평가금액 (INVEST 전용, 수동 갱신)
+    private Long loanAmount;       // 대출 실행 금액(원금, 처음 빌린 금액) (LOAN 전용)
+    private BigDecimal loanRate;   // 연이자율(%) e.g. 5.25 (LOAN 전용)
+    private String loanMethod;     // 상환방식: EQUAL_PAYMENT / EQUAL_PRINCIPAL / BULLET (LOAN 전용)
+    private Integer loanMonths;    // 대출기간(개월) (LOAN 전용)
+    private LocalDate loanStart;   // 대출시작일 (LOAN 전용)
     private Integer sortOrder;    // 표시 순서 (타입 내 정렬)
     private LocalDateTime createdAt;
     private LocalDateTime updatedAt;

src/main/java/com/sb/web/account/dto/WalletRequest.java

@@ -1,10 +1,13 @@
 package com.sb.web.account.dto;
 
+import jakarta.validation.constraints.DecimalMax;
+import jakarta.validation.constraints.DecimalMin;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.Pattern;
 import jakarta.validation.constraints.Size;
 import lombok.Data;
 
+import java.math.BigDecimal;
 import java.time.LocalDate;
 
 /**
@@ -37,4 +40,17 @@ public class WalletRequest {
 
     /** 현재 평가금액 (INVEST 전용, 수동 갱신) */
     private Long currentValue;
+
+    // ===== 대출(LOAN) 전용 =====
+    private Long loanAmount;       // 대출 실행 금액(원금)
+
+    @DecimalMin(value = "0.0", inclusive = true)
+    @DecimalMax(value = "100.0", message = "이자율은 100% 이하여야 합니다.")
+    private BigDecimal loanRate;   // 연이자율(%)
+
+    @Pattern(regexp = "EQUAL_PAYMENT|EQUAL_PRINCIPAL|BULLET|", message = "상환방식이 올바르지 않습니다.")
+    private String loanMethod;     // 상환방식
+
+    private Integer loanMonths;    // 대출기간(개월)
+    private LocalDate loanStart;   // 대출시작일
 }

src/main/java/com/sb/web/account/dto/WalletResponse.java

@@ -4,6 +4,7 @@ import com.sb.web.account.domain.Wallet;
 import lombok.Builder;
 import lombok.Data;
 
+import java.math.BigDecimal;
 import java.time.LocalDate;
 
 /**
@@ -31,6 +32,13 @@ public class WalletResponse {
     private Long currentValue;    // 평가액 직접입력값(퇴직연금·연금 등 수동 갱신). 있으면 총평가로 사용
     private Boolean manualValuation; // true면 평가액 직접입력형(종목 자동계산 대신)
 
+    // 대출(LOAN) 전용
+    private Long loanAmount;       // 대출 실행 금액(원금)
+    private BigDecimal loanRate;   // 연이자율(%) e.g. 5.25
+    private String loanMethod;     // EQUAL_PAYMENT / EQUAL_PRINCIPAL / BULLET
+    private Integer loanMonths;    // 대출기간(개월)
+    private LocalDate loanStart;   // 대출시작일
+
     public static WalletResponse from(Wallet w, long balance) {
         return WalletResponse.builder()
                 .id(w.getId())
@@ -43,6 +51,11 @@ public class WalletResponse {
                 .openingDate(w.getOpeningDate())
                 .balance(balance)
                 .currentValue(w.getCurrentValue())
+                .loanAmount(w.getLoanAmount())
+                .loanRate(w.getLoanRate())
+                .loanMethod(w.getLoanMethod())
+                .loanMonths(w.getLoanMonths())
+                .loanStart(w.getLoanStart())
                 .build();
     }
 }

src/main/java/com/sb/web/account/service/AccountService.java

@@ -535,6 +535,12 @@ public class AccountService {
         wallet.setOpeningBalance(req.getOpeningBalance() != null ? req.getOpeningBalance() : 0L);
         wallet.setOpeningDate(req.getOpeningDate());
         wallet.setCurrentValue("INVEST".equals(req.getType()) ? req.getCurrentValue() : null);
+        boolean isLoan = "LOAN".equals(req.getType());
+        wallet.setLoanAmount(isLoan ? req.getLoanAmount() : null);
+        wallet.setLoanRate(isLoan ? req.getLoanRate() : null);
+        wallet.setLoanMethod(isLoan ? blankToNull(req.getLoanMethod()) : null);
+        wallet.setLoanMonths(isLoan ? req.getLoanMonths() : null);
+        wallet.setLoanStart(isLoan ? req.getLoanStart() : null);
         walletMapper.update(wallet);
         return WalletResponse.from(wallet, balanceMap(memberId).getOrDefault(id, wallet.getOpeningBalance()));
     }
@@ -564,6 +570,7 @@ public class AccountService {
     }
 
     private Wallet toWallet(WalletRequest req) {
+        boolean isLoan = "LOAN".equals(req.getType());
         return Wallet.builder()
                 .type(req.getType())
                 .name(req.getName().trim())
@@ -573,6 +580,11 @@ public class AccountService {
                 .openingBalance(req.getOpeningBalance() != null ? req.getOpeningBalance() : 0L)
                 .openingDate(req.getOpeningDate())
                 .currentValue("INVEST".equals(req.getType()) ? req.getCurrentValue() : null)
+                .loanAmount(isLoan ? req.getLoanAmount() : null)
+                .loanRate(isLoan ? req.getLoanRate() : null)
+                .loanMethod(isLoan ? blankToNull(req.getLoanMethod()) : null)
+                .loanMonths(isLoan ? req.getLoanMonths() : null)
+                .loanStart(isLoan ? req.getLoanStart() : null)
                 .build();
     }