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/resources/db/account.sql

@@ -28,6 +28,11 @@ ALTER TABLE wallet ADD COLUMN IF NOT EXISTS opening_balance BIGINT NOT NULL DEFA
 ALTER TABLE wallet ADD COLUMN IF NOT EXISTS opening_date DATE NULL;
 ALTER TABLE wallet ADD COLUMN IF NOT EXISTS current_value BIGINT NULL;
 ALTER TABLE wallet ADD COLUMN IF NOT EXISTS sort_order INT NOT NULL DEFAULT 0;
+ALTER TABLE wallet ADD COLUMN IF NOT EXISTS loan_rate    DECIMAL(7,4) NULL COMMENT '연이자율(%) 예: 5.2500';
+ALTER TABLE wallet ADD COLUMN IF NOT EXISTS loan_method  VARCHAR(20)  NULL COMMENT '상환방식: EQUAL_PAYMENT/EQUAL_PRINCIPAL/BULLET';
+ALTER TABLE wallet ADD COLUMN IF NOT EXISTS loan_months  INT          NULL COMMENT '대출기간(개월)';
+ALTER TABLE wallet ADD COLUMN IF NOT EXISTS loan_start   DATE         NULL COMMENT '대출시작일';
+ALTER TABLE wallet ADD COLUMN IF NOT EXISTS loan_amount  BIGINT       NULL COMMENT '대출 실행 금액(원금, 처음 빌린 금액)';
 -- 계좌번호 암호화 저장(AES-GCM)으로 평문보다 길어 VARCHAR(255) 필요 — 운영 적용 완료(CREATE TABLE 정의에 반영).
 -- 매 기동 MODIFY 는 라이브 테이블 락 위험이 있어 제거. 기존 환경 확장이 필요하면 1회 수동 적용:
 --   ALTER TABLE wallet MODIFY account_number VARCHAR(255) NULL;

src/main/resources/mapper/WalletMapper.xml

@@ -15,13 +15,20 @@
         <result property="openingBalance" column="opening_balance"/>
         <result property="openingDate" column="opening_date"/>
         <result property="currentValue" column="current_value"/>
+        <result property="loanAmount" column="loan_amount"/>
+        <result property="loanRate" column="loan_rate"/>
+        <result property="loanMethod" column="loan_method"/>
+        <result property="loanMonths" column="loan_months"/>
+        <result property="loanStart" column="loan_start"/>
         <result property="sortOrder" column="sort_order"/>
         <result property="createdAt" column="created_at"/>
         <result property="updatedAt" column="updated_at"/>
     </resultMap>
 
     <sql id="cols">id, member_id, type, name, issuer, account_number, card_type,
-        opening_balance, opening_date, current_value, sort_order, created_at, updated_at</sql>
+        opening_balance, opening_date, current_value,
+        loan_amount, loan_rate, loan_method, loan_months, loan_start,
+        sort_order, created_at, updated_at</sql>
 
     <select id="findByMember" parameterType="long" resultMap="walletResultMap">
         SELECT <include refid="cols"/> FROM wallet
@@ -37,10 +44,14 @@
     <insert id="insert" parameterType="com.sb.web.account.domain.Wallet"
             useGeneratedKeys="true" keyProperty="id">
         INSERT INTO wallet (member_id, type, name, issuer, account_number, card_type,
-                            opening_balance, opening_date, current_value, sort_order, created_at, updated_at)
+                            opening_balance, opening_date, current_value,
+                            loan_amount, loan_rate, loan_method, loan_months, loan_start,
+                            sort_order, created_at, updated_at)
         VALUES (#{memberId}, #{type}, #{name}, #{issuer},
                 #{accountNumber, typeHandler=com.sb.web.common.crypto.EncryptedStringTypeHandler}, #{cardType},
-                #{openingBalance}, #{openingDate}, #{currentValue}, #{sortOrder}, NOW(), NOW())
+                #{openingBalance}, #{openingDate}, #{currentValue},
+                #{loanAmount}, #{loanRate}, #{loanMethod}, #{loanMonths}, #{loanStart},
+                #{sortOrder}, NOW(), NOW())
     </insert>
 
     <update id="update" parameterType="com.sb.web.account.domain.Wallet">
@@ -49,7 +60,10 @@
             account_number = #{accountNumber, typeHandler=com.sb.web.common.crypto.EncryptedStringTypeHandler},
             card_type = #{cardType},
             opening_balance = #{openingBalance}, opening_date = #{openingDate},
-            current_value = #{currentValue}
+            current_value = #{currentValue},
+            loan_amount = #{loanAmount},
+            loan_rate = #{loanRate}, loan_method = #{loanMethod},
+            loan_months = #{loanMonths}, loan_start = #{loanStart}
         WHERE id = #{id} AND member_id = #{memberId}
     </update>