feat(core): ChargebackGrade VO 세트 + Mapper (도메인 P1-3-b)

V28 chargeback_grade와 ga-core 동기화. 차등 환수 비즈니스 로직은 P1-3-c.

신규 패키지: com.ga.core.vo.chargeback, com.ga.core.mapper.chargeback

VO 세트:
- ChargebackGradeVO (BaseVO 상속, monthsFrom/monthsTo NULL=무한대)
- ChargebackGradeResp (productCategoryName + monthsRange 표시 문자열)
- ChargebackGradeSaveReq (@Valid: @Min(0) monthsFrom/percent)
- ChargebackGradeSearchParam (productCategory/monthsElapsed/effectiveDate)

ChargebackGradeMapper:
- 표준 CRUD
- selectByMonths(productCategory, monthsElapsed, baseDate)
  → 해당 경과월에 적용되는 환수 비율 1건 (months_from <= monthsElapsed
    AND (months_to IS NULL OR months_to >= monthsElapsed)) + 유효기간
    + product_category NULL 안전 비교 + LIMIT 1 최신 우선
- selectAll(baseDate) — months_from ASC + product_category NULLS FIRST
- selectByCategory(productCategory, baseDate)

XML 공통 activeCondition SQL fragment로 중복 제거.

ga-core/src/main/java/com/ga/core/mapper/chargeback/ChargebackGradeMapper.java

@@ -0,0 +1,37 @@
+package com.ga.core.mapper.chargeback;
+
+import com.ga.core.vo.chargeback.ChargebackGradeResp;
+import com.ga.core.vo.chargeback.ChargebackGradeSearchParam;
+import com.ga.core.vo.chargeback.ChargebackGradeVO;
+import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
+
+import java.util.List;
+
+@Mapper
+public interface ChargebackGradeMapper {
+
+    List<ChargebackGradeResp> selectList(ChargebackGradeSearchParam param);
+
+    ChargebackGradeResp selectDetailById(@Param("gradeId") Long gradeId);
+
+    ChargebackGradeVO selectById(@Param("gradeId") Long gradeId);
+
+    /** 해약 경과월에 적용되는 환수 비율 구간 1건 조회 (차등 환수 계산 핵심) */
+    ChargebackGradeVO selectByMonths(@Param("productCategory") String productCategory,
+                                     @Param("monthsElapsed") Integer monthsElapsed,
+                                     @Param("baseDate") String baseDate);
+
+    /** 특정 시점 활성 전체 구간 조회 (months_from ASC) */
+    List<ChargebackGradeVO> selectAll(@Param("baseDate") String baseDate);
+
+    /** 카테고리별 활성 구간 조회 */
+    List<ChargebackGradeVO> selectByCategory(@Param("productCategory") String productCategory,
+                                              @Param("baseDate") String baseDate);
+
+    int insert(ChargebackGradeVO vo);
+
+    int update(ChargebackGradeVO vo);
+
+    int updateStatus(@Param("gradeId") Long gradeId, @Param("isActive") Boolean isActive);
+}

ga-core/src/main/java/com/ga/core/vo/chargeback/ChargebackGradeResp.java

@@ -0,0 +1,20 @@
+package com.ga.core.vo.chargeback;
+
+import lombok.Data;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+
+@Data
+public class ChargebackGradeResp {
+    private Long gradeId;
+    private String productCategory;
+    private String productCategoryName;
+    private Integer monthsFrom;
+    private Integer monthsTo;
+    private String monthsRange;         // "1~12개월", "85개월 이상" 형태 표시용
+    private BigDecimal chargebackPercent;
+    private LocalDate effectiveFrom;
+    private LocalDate effectiveTo;
+    private Boolean isActive;
+}

ga-core/src/main/java/com/ga/core/vo/chargeback/ChargebackGradeSaveReq.java

@@ -0,0 +1,30 @@
+package com.ga.core.vo.chargeback;
+
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Positive;
+import lombok.Data;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+
+@Data
+public class ChargebackGradeSaveReq {
+
+    private String productCategory;   // NULL = 전체 상품
+
+    @NotNull(message = "경과월 시작은 필수입니다")
+    @Min(value = 0, message = "경과월 시작은 0 이상이어야 합니다")
+    private Integer monthsFrom;
+
+    private Integer monthsTo;         // NULL = 무한대
+
+    @NotNull(message = "환수율은 필수입니다")
+    @Min(value = 0, message = "환수율은 0 이상이어야 합니다")
+    private BigDecimal chargebackPercent;
+
+    @NotNull(message = "적용 시작일은 필수입니다")
+    private LocalDate effectiveFrom;
+
+    private LocalDate effectiveTo;
+}

ga-core/src/main/java/com/ga/core/vo/chargeback/ChargebackGradeSearchParam.java

@@ -0,0 +1,13 @@
+package com.ga.core.vo.chargeback;
+
+import com.ga.common.model.SearchParam;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+
+@Data
+@EqualsAndHashCode(callSuper = true)
+public class ChargebackGradeSearchParam extends SearchParam {
+    private String productCategory;
+    private Integer monthsElapsed;    // 해당 경과월에 해당하는 구간 필터
+    private String effectiveDate;     // YYYY-MM-DD — 해당 날짜 유효 구간 필터
+}

ga-core/src/main/java/com/ga/core/vo/chargeback/ChargebackGradeVO.java

@@ -0,0 +1,24 @@
+package com.ga.core.vo.chargeback;
+
+import lombok.Data;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+
+@Data
+public class ChargebackGradeVO {
+    private Long gradeId;
+    private String productCategory;    // NULL = ALL 상품
+    private Integer monthsFrom;        // 해약 경과월 시작 (이상)
+    private Integer monthsTo;          // 해약 경과월 종료 (이하), NULL = 무한대
+    private BigDecimal chargebackPercent;
+    private LocalDate effectiveFrom;
+    private LocalDate effectiveTo;     // NULL = 현재 유효
+    private Boolean isActive;
+
+    private LocalDateTime createdAt;
+    private Long createdBy;
+    private LocalDateTime updatedAt;
+    private Long updatedBy;
+}

ga-core/src/main/resources/mapper/chargeback/ChargebackGradeMapper.xml

@@ -0,0 +1,188 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
+        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="com.ga.core.mapper.chargeback.ChargebackGradeMapper">
+
+    <!-- ==================== ResultMap ==================== -->
+
+    <!-- chargeback_grade 테이블 1:1 매핑 (CUD용) -->
+    <resultMap id="VOMap" type="com.ga.core.vo.chargeback.ChargebackGradeVO">
+        <id  property="gradeId"           column="grade_id"/>
+        <result property="productCategory"    column="product_category"/>
+        <result property="monthsFrom"         column="months_from"/>
+        <result property="monthsTo"           column="months_to"/>
+        <result property="chargebackPercent"  column="chargeback_percent"/>
+        <result property="effectiveFrom"      column="effective_from"/>
+        <result property="effectiveTo"        column="effective_to"/>
+        <result property="isActive"           column="is_active"/>
+        <result property="createdAt"          column="created_at"/>
+        <result property="createdBy"          column="created_by"/>
+        <result property="updatedAt"          column="updated_at"/>
+        <result property="updatedBy"          column="updated_by"/>
+    </resultMap>
+
+    <!-- 코드명 + monthsRange 포함 API 응답용 -->
+    <resultMap id="RespMap" type="com.ga.core.vo.chargeback.ChargebackGradeResp">
+        <id  property="gradeId"               column="grade_id"/>
+        <result property="productCategory"        column="product_category"/>
+        <result property="productCategoryName"    column="product_category_name"/>
+        <result property="monthsFrom"             column="months_from"/>
+        <result property="monthsTo"               column="months_to"/>
+        <result property="monthsRange"            column="months_range"/>
+        <result property="chargebackPercent"      column="chargeback_percent"/>
+        <result property="effectiveFrom"          column="effective_from"/>
+        <result property="effectiveTo"            column="effective_to"/>
+        <result property="isActive"               column="is_active"/>
+    </resultMap>
+
+    <!-- ==================== 공통 SELECT 컬럼 ==================== -->
+
+    <sql id="selectRespCols">
+        g.grade_id,
+        g.product_category,
+        (SELECT cc.code_name FROM common_code cc
+         WHERE cc.group_code = 'PRODUCT_CATEGORY' AND cc.code = g.product_category) AS product_category_name,
+        g.months_from,
+        g.months_to,
+        CASE
+            WHEN g.months_to IS NULL THEN g.months_from || '개월 이상'
+            ELSE g.months_from || '~' || g.months_to || '개월'
+        END AS months_range,
+        g.chargeback_percent,
+        g.effective_from,
+        g.effective_to,
+        g.is_active
+    </sql>
+
+    <!-- 활성 유효기간 공통 조건 -->
+    <sql id="activeCondition">
+        AND g.is_active = TRUE
+        AND g.effective_from &lt;= #{baseDate}::DATE
+        AND (g.effective_to IS NULL OR g.effective_to >= #{baseDate}::DATE)
+    </sql>
+
+    <!-- ==================== SELECT ==================== -->
+
+    <!-- 목록 조회 (검색 조건 + 페이징) -->
+    <select id="selectList" parameterType="com.ga.core.vo.chargeback.ChargebackGradeSearchParam"
+            resultMap="RespMap">
+        SELECT <include refid="selectRespCols"/>
+        FROM chargeback_grade g
+        <where>
+            <if test="productCategory != null and productCategory != ''">
+                AND g.product_category = #{productCategory}
+            </if>
+            <if test="monthsElapsed != null">
+                AND g.months_from &lt;= #{monthsElapsed}
+                AND (g.months_to IS NULL OR g.months_to >= #{monthsElapsed})
+            </if>
+            <if test="effectiveDate != null and effectiveDate != ''">
+                AND g.effective_from &lt;= #{effectiveDate}::DATE
+                AND (g.effective_to IS NULL OR g.effective_to >= #{effectiveDate}::DATE)
+            </if>
+        </where>
+        ORDER BY g.months_from, g.effective_from DESC
+        <if test="pageSize != null and pageSize > 0">
+            LIMIT #{pageSize} OFFSET #{offset}
+        </if>
+    </select>
+
+    <!-- 단건 조회 (Resp: 코드명 포함) -->
+    <select id="selectDetailById" resultMap="RespMap">
+        SELECT <include refid="selectRespCols"/>
+        FROM chargeback_grade g
+        WHERE g.grade_id = #{gradeId}
+    </select>
+
+    <!-- 단건 조회 (VO: CUD용) -->
+    <select id="selectById" resultMap="VOMap">
+        SELECT grade_id, product_category, months_from, months_to,
+               chargeback_percent, effective_from, effective_to, is_active,
+               created_at, created_by, updated_at, updated_by
+        FROM chargeback_grade
+        WHERE grade_id = #{gradeId}
+    </select>
+
+    <!--
+        해약 경과월에 적용되는 환수 비율 구간 1건 조회.
+        months_from <= monthsElapsed AND (months_to IS NULL OR months_to >= monthsElapsed)
+        product_category NULL은 전체 상품 적용 행이므로 NULL 안전 비교 처리.
+        effective_from DESC로 최신 개정본 우선 반환.
+    -->
+    <select id="selectByMonths" resultMap="VOMap">
+        SELECT grade_id, product_category, months_from, months_to,
+               chargeback_percent, effective_from, effective_to, is_active,
+               created_at, created_by, updated_at, updated_by
+        FROM chargeback_grade g
+        WHERE g.months_from &lt;= #{monthsElapsed}
+          AND (g.months_to IS NULL OR g.months_to >= #{monthsElapsed})
+          AND (g.product_category = #{productCategory}
+               OR (#{productCategory} IS NULL AND g.product_category IS NULL))
+          <include refid="activeCondition"/>
+        ORDER BY g.effective_from DESC
+        LIMIT 1
+    </select>
+
+    <!-- 특정 시점 활성 전체 구간 (months_from ASC 정렬) -->
+    <select id="selectAll" resultMap="VOMap">
+        SELECT grade_id, product_category, months_from, months_to,
+               chargeback_percent, effective_from, effective_to, is_active,
+               created_at, created_by, updated_at, updated_by
+        FROM chargeback_grade g
+        WHERE 1=1
+          <include refid="activeCondition"/>
+        ORDER BY g.product_category NULLS FIRST, g.months_from
+    </select>
+
+    <!-- 카테고리별 활성 구간 (months_from ASC) -->
+    <select id="selectByCategory" resultMap="VOMap">
+        SELECT grade_id, product_category, months_from, months_to,
+               chargeback_percent, effective_from, effective_to, is_active,
+               created_at, created_by, updated_at, updated_by
+        FROM chargeback_grade g
+        WHERE (g.product_category = #{productCategory}
+               OR (#{productCategory} IS NULL AND g.product_category IS NULL))
+          <include refid="activeCondition"/>
+        ORDER BY g.months_from
+    </select>
+
+    <!-- ==================== INSERT ==================== -->
+
+    <insert id="insert" parameterType="com.ga.core.vo.chargeback.ChargebackGradeVO"
+            useGeneratedKeys="true" keyProperty="gradeId">
+        INSERT INTO chargeback_grade (
+            product_category, months_from, months_to,
+            chargeback_percent, effective_from, effective_to,
+            is_active, created_at, created_by
+        ) VALUES (
+            #{productCategory}, #{monthsFrom}, #{monthsTo},
+            #{chargebackPercent}, #{effectiveFrom}, #{effectiveTo},
+            COALESCE(#{isActive}, TRUE), NOW(), #{createdBy}
+        )
+    </insert>
+
+    <!-- ==================== UPDATE ==================== -->
+
+    <update id="update" parameterType="com.ga.core.vo.chargeback.ChargebackGradeVO">
+        UPDATE chargeback_grade
+        <set>
+            <if test="monthsFrom != null">months_from = #{monthsFrom},</if>
+            <if test="monthsTo != null">months_to = #{monthsTo},</if>
+            <if test="chargebackPercent != null">chargeback_percent = #{chargebackPercent},</if>
+            <if test="effectiveFrom != null">effective_from = #{effectiveFrom},</if>
+            <if test="effectiveTo != null">effective_to = #{effectiveTo},</if>
+            <if test="isActive != null">is_active = #{isActive},</if>
+            updated_at = NOW(),
+            updated_by = #{updatedBy}
+        </set>
+        WHERE grade_id = #{gradeId}
+    </update>
+
+    <!-- 활성 여부만 변경 -->
+    <update id="updateStatus">
+        UPDATE chargeback_grade
+        SET is_active = #{isActive}, updated_at = NOW()
+        WHERE grade_id = #{gradeId}
+    </update>
+
+</mapper>