feat: 가계부·게시판 백엔드 API 구현

- com.sb.web 패키지로 재구성: account / auth / board / user / admin / common
- 가계부(account): 내역(필터), 계좌·순자산, 예산, 분류, 정기 거래, 투자 포트폴리오
  (종목·매매 이력, 이동평균 평단·실현/평가손익)
- MyBatis + MariaDB + Redis 세션, BCrypt
- 스키마 자동 초기화(db/*.sql, 멱등), 사용자별 데이터 격리(member_id)
- 문서: docs/BACKEND.md, .env.example

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/resources/mapper/RecurringMapper.xml

@@ -0,0 +1,81 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
+        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="com.sb.web.account.mapper.RecurringMapper">
+
+    <resultMap id="recurringResultMap" type="com.sb.web.account.domain.Recurring">
+        <id property="id" column="id"/>
+        <result property="memberId" column="member_id"/>
+        <result property="title" column="title"/>
+        <result property="type" column="type"/>
+        <result property="amount" column="amount"/>
+        <result property="category" column="category"/>
+        <result property="memo" column="memo"/>
+        <result property="walletId" column="wallet_id"/>
+        <result property="walletName" column="wallet_name"/>
+        <result property="toWalletId" column="to_wallet_id"/>
+        <result property="toWalletName" column="to_wallet_name"/>
+        <result property="frequency" column="frequency"/>
+        <result property="dayOfMonth" column="day_of_month"/>
+        <result property="dayOfWeek" column="day_of_week"/>
+        <result property="monthOfYear" column="month_of_year"/>
+        <result property="startDate" column="start_date"/>
+        <result property="endDate" column="end_date"/>
+        <result property="lastRunDate" column="last_run_date"/>
+        <result property="active" column="active"/>
+    </resultMap>
+
+    <sql id="selectJoin">
+        SELECT r.id, r.member_id, r.title, r.type, r.amount, r.category, r.memo,
+               r.wallet_id, w.name AS wallet_name, r.to_wallet_id, tw.name AS to_wallet_name,
+               r.frequency, r.day_of_month, r.day_of_week, r.month_of_year,
+               r.start_date, r.end_date, r.last_run_date, r.active
+        FROM recurring r
+        LEFT JOIN wallet w  ON w.id  = r.wallet_id
+        LEFT JOIN wallet tw ON tw.id = r.to_wallet_id
+    </sql>
+
+    <select id="findByMember" parameterType="long" resultMap="recurringResultMap">
+        <include refid="selectJoin"/>
+        WHERE r.member_id = #{memberId}
+        ORDER BY r.active DESC, r.title
+    </select>
+
+    <select id="findActiveByMember" parameterType="long" resultMap="recurringResultMap">
+        <include refid="selectJoin"/>
+        WHERE r.member_id = #{memberId} AND r.active = 1
+    </select>
+
+    <select id="findByIdAndMember" resultMap="recurringResultMap">
+        <include refid="selectJoin"/>
+        WHERE r.id = #{id} AND r.member_id = #{memberId}
+    </select>
+
+    <insert id="insert" parameterType="com.sb.web.account.domain.Recurring"
+            useGeneratedKeys="true" keyProperty="id">
+        INSERT INTO recurring (member_id, title, type, amount, category, memo, wallet_id, to_wallet_id,
+                               frequency, day_of_month, day_of_week, month_of_year,
+                               start_date, end_date, last_run_date, active, created_at, updated_at)
+        VALUES (#{memberId}, #{title}, #{type}, #{amount}, #{category}, #{memo}, #{walletId}, #{toWalletId},
+                #{frequency}, #{dayOfMonth}, #{dayOfWeek}, #{monthOfYear},
+                #{startDate}, #{endDate}, #{lastRunDate}, #{active}, NOW(), NOW())
+    </insert>
+
+    <update id="update" parameterType="com.sb.web.account.domain.Recurring">
+        UPDATE recurring
+        SET title = #{title}, type = #{type}, amount = #{amount}, category = #{category}, memo = #{memo},
+            wallet_id = #{walletId}, to_wallet_id = #{toWalletId},
+            frequency = #{frequency}, day_of_month = #{dayOfMonth}, day_of_week = #{dayOfWeek},
+            month_of_year = #{monthOfYear}, start_date = #{startDate}, end_date = #{endDate}, active = #{active}
+        WHERE id = #{id} AND member_id = #{memberId}
+    </update>
+
+    <delete id="delete">
+        DELETE FROM recurring WHERE id = #{id} AND member_id = #{memberId}
+    </delete>
+
+    <update id="updateLastRun">
+        UPDATE recurring SET last_run_date = #{lastRunDate} WHERE id = #{id}
+    </update>
+
+</mapper>