feat: 인앱 결제(Google Play) 스캐폴드 + 멤버십 만료 처리

- member.plan_expires_at + iap_purchase 테이블(중복 결제 방지)
- POST /api/billing/google/verify: 구매 검증 후 PREMIUM 부여/갱신(만료 연장), 세션 plan 즉시 동기화
- GET /api/billing/products: 구독 상품(월간/연간)
- 테스트 모드(billing.test-mode=true): test- 토큰 검증 없이 승인 → 전 과정 테스트 가능
- GooglePlayVerifier 인터페이스 + 스텁(실연동 지점), 실연동 시 구현체 교체
- 관리자 수동 plan 변경은 만료일 없이(영구), 결제는 만료일 부여
- 만료 자동 강등 스케줄러(매시), MemberResponse.planExpiresAt 노출

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

src/main/java/com/sb/web/SbBtApplication.java

@@ -7,7 +7,7 @@ import org.springframework.scheduling.annotation.EnableScheduling;
 
 @SpringBootApplication
 @EnableScheduling
-@MapperScan({"com.sb.web.user.mapper", "com.sb.web.auth.mapper", "com.sb.web.board.mapper", "com.sb.web.account.mapper", "com.sb.web.admin.mapper", "com.sb.web.point.mapper"})
+@MapperScan({"com.sb.web.user.mapper", "com.sb.web.auth.mapper", "com.sb.web.board.mapper", "com.sb.web.account.mapper", "com.sb.web.admin.mapper", "com.sb.web.point.mapper", "com.sb.web.billing.mapper"})
 public class SbBtApplication {
 
 	public static void main(String[] args) {

src/main/java/com/sb/web/auth/domain/Member.java

@@ -30,6 +30,7 @@ public class Member implements Serializable {
     private String profileImage;  // 사용자 지정 프로필 이미지(data URL). 우선순위: profileImage > googlePicture > 이니셜
     private String role;         // USER / ADMIN
     private String plan;         // FREE / PREMIUM (멤버십)
+    private LocalDateTime planExpiresAt; // 유료 멤버십 만료일 (NULL=만료없음/무료)
     private Long points;         // 활동 포인트 (게시판 글/댓글 작성 보상)
     private String status;       // ACTIVE / SUSPENDED / WITHDRAWN
     private LocalDateTime createdAt;

src/main/java/com/sb/web/auth/dto/MemberResponse.java

@@ -18,6 +18,7 @@ public class MemberResponse {
     private String provider;
     private String role;
     private String plan; // FREE / PREMIUM
+    private java.time.LocalDateTime planExpiresAt; // 유료 멤버십 만료일
     private Long points; // 활동 포인트
     private String googlePicture; // 구글 아바타 URL
     private String profileImage;  // 사용자 지정 프로필 이미지(data URL)
@@ -31,6 +32,7 @@ public class MemberResponse {
                 .provider(m.getProvider())
                 .role(m.getRole())
                 .plan(m.getPlan())
+                .planExpiresAt(m.getPlanExpiresAt())
                 .points(m.getPoints())
                 .googlePicture(m.getGooglePicture())
                 .profileImage(m.getProfileImage())

src/main/java/com/sb/web/auth/mapper/AuthSessionMapper.java

@@ -21,6 +21,9 @@ public interface AuthSessionMapper {
     /** 프로필 변경 시 백업 세션의 표시 이름 동기화 */
     int updateName(@Param("token") String token, @Param("name") String name);
 
+    /** 멤버십 변경 시 백업 세션의 plan 동기화 */
+    int updatePlan(@Param("token") String token, @Param("plan") String plan);
+
     int delete(@Param("token") String token);
 
     int deleteExpired(@Param("now") LocalDateTime now);

src/main/java/com/sb/web/auth/mapper/MemberMapper.java

@@ -50,6 +50,13 @@ public interface MemberMapper {
 
     int updatePlan(@Param("id") Long id, @Param("plan") String plan);
 
+    /** 결제로 멤버십 부여/갱신 (plan + 만료일) */
+    int updateMembership(@Param("id") Long id, @Param("plan") String plan,
+                         @Param("expiresAt") java.time.LocalDateTime expiresAt);
+
+    /** 만료된 유료회원을 FREE 로 강등 (스케줄러). 강등된 건수 반환 */
+    int downgradeExpired();
+
     int updateStatus(@Param("id") Long id, @Param("status") String status);
 
     int deleteById(@Param("id") Long id);

src/main/java/com/sb/web/auth/service/AuthService.java

@@ -402,6 +402,32 @@ public class AuthService {
         }
     }
 
+    /** 결제/멤버십 변경 시 활성 세션(Redis + DB 백업)의 plan 을 즉시 맞춘다 (재로그인 없이 유료 기능 개방). */
+    public void syncSessionPlan(String token, String plan) {
+        if (token == null || token.isBlank()) {
+            return;
+        }
+        String key = SESSION_PREFIX + token;
+        try {
+            Object cached = redisTemplate.opsForValue().get(key);
+            if (cached instanceof SessionUser u) {
+                u.setPlan(plan);
+                Long ttl = redisTemplate.getExpire(key, java.util.concurrent.TimeUnit.SECONDS);
+                Duration remain = (ttl != null && ttl > 0)
+                        ? Duration.ofSeconds(ttl)
+                        : (u.isRememberMe() ? REMEMBER_TTL : SESSION_TTL);
+                redisTemplate.opsForValue().set(key, u, remain);
+            }
+        } catch (Exception e) {
+            log.warn("[billing] Redis 세션 plan 동기화 실패(무시): {}", e.toString());
+        }
+        try {
+            authSessionMapper.updatePlan(token, plan);
+        } catch (Exception ignore) {
+            // DB 백업 동기화 실패해도 다음 로그인 시 갱신됨
+        }
+    }
+
     /**
      * 비밀번호 변경 (본인). 현재 비밀번호 검증 후 새 비밀번호로 교체.
      */

src/main/java/com/sb/web/billing/BillingController.java

@@ -0,0 +1,39 @@
+package com.sb.web.billing;
+
+import com.sb.web.auth.dto.SessionUser;
+import com.sb.web.auth.web.AuthInterceptor;
+import com.sb.web.billing.dto.MembershipResponse;
+import com.sb.web.billing.dto.ProductResponse;
+import com.sb.web.billing.dto.VerifyRequest;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+/**
+ * 인앱 결제 API. (/api/billing/** — 로그인 필요)
+ *   GET  /products         구독 상품 목록
+ *   POST /google/verify    Google Play 구매 검증 → 멤버십 부여
+ */
+@RestController
+@RequestMapping("/api/billing")
+@RequiredArgsConstructor
+public class BillingController {
+
+    private final BillingService billingService;
+
+    @GetMapping("/products")
+    public List<ProductResponse> products() {
+        return billingService.products();
+    }
+
+    @PostMapping("/google/verify")
+    public MembershipResponse verifyGoogle(
+            @Valid @RequestBody VerifyRequest req,
+            @RequestAttribute(AuthInterceptor.CURRENT_MEMBER) SessionUser current,
+            HttpServletRequest request) {
+        return billingService.verifyGoogle(current.getId(), AuthInterceptor.resolveToken(request), req);
+    }
+}

src/main/java/com/sb/web/billing/BillingService.java

@@ -0,0 +1,111 @@
+package com.sb.web.billing;
+
+import com.sb.web.auth.domain.Member;
+import com.sb.web.auth.mapper.MemberMapper;
+import com.sb.web.auth.service.AuthService;
+import com.sb.web.billing.domain.IapPurchase;
+import com.sb.web.billing.dto.MembershipResponse;
+import com.sb.web.billing.dto.ProductResponse;
+import com.sb.web.billing.dto.VerifyRequest;
+import com.sb.web.billing.mapper.IapPurchaseMapper;
+import com.sb.web.common.exception.ApiException;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.HttpStatus;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDateTime;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * 인앱 결제(Google Play) 처리 — 상품 목록, 구매 검증 후 멤버십 부여.
+ * 스캐폴드: billing.test-mode=true 면 'test-' 토큰을 실제 검증 없이 승인한다.
+ */
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class BillingService {
+
+    private final MemberMapper memberMapper;
+    private final IapPurchaseMapper purchaseMapper;
+    private final GooglePlayVerifier googlePlayVerifier;
+    private final AuthService authService;
+
+    /** 실연동 전 기본 true — 'test-' 토큰으로 결제 흐름 테스트 가능 */
+    @Value("${billing.test-mode:true}")
+    private boolean testMode;
+
+    /** 구독 상품 카탈로그 (가격은 표시용 — 실제 금액은 Play Console 기준) */
+    private static final Map<String, ProductResponse> CATALOG = new LinkedHashMap<>();
+    static {
+        CATALOG.put("premium_monthly", new ProductResponse("premium_monthly", "프리미엄 월간", 1, 2900));
+        CATALOG.put("premium_yearly", new ProductResponse("premium_yearly", "프리미엄 연간", 12, 29000));
+    }
+
+    public List<ProductResponse> products() {
+        return List.copyOf(CATALOG.values());
+    }
+
+    /**
+     * Google Play 구매 검증 후 멤버십(PREMIUM) 부여/갱신.
+     * 같은 구매 토큰은 한 번만 처리(멱등). 세션 plan 도 즉시 동기화.
+     */
+    @Transactional
+    public MembershipResponse verifyGoogle(Long memberId, String sessionToken, VerifyRequest req) {
+        ProductResponse product = CATALOG.get(req.getProductId());
+        if (product == null) {
+            throw new ApiException(HttpStatus.BAD_REQUEST, "알 수 없는 상품입니다.");
+        }
+        String token = req.getPurchaseToken();
+
+        // 이미 처리된 결제면 현재 상태 반환 (중복 지급 방지)
+        IapPurchase existing = purchaseMapper.findByToken(token);
+        if (existing != null) {
+            return MembershipResponse.of(mustFind(memberId));
+        }
+
+        boolean test = testMode || token.startsWith("test-");
+        String platform;
+        if (test) {
+            platform = "TEST";
+        } else {
+            platform = "GOOGLE_PLAY";
+            if (!googlePlayVerifier.verify(req.getProductId(), token)) {
+                throw new ApiException(HttpStatus.BAD_REQUEST, "결제 검증에 실패했습니다.");
+            }
+        }
+
+        // 기존 만료일이 미래면 그 시점부터 연장, 아니면 지금부터
+        Member member = mustFind(memberId);
+        LocalDateTime now = LocalDateTime.now();
+        LocalDateTime base = (member.getPlanExpiresAt() != null && member.getPlanExpiresAt().isAfter(now))
+                ? member.getPlanExpiresAt() : now;
+        LocalDateTime expires = base.plusMonths(product.getMonths());
+
+        memberMapper.updateMembership(memberId, "PREMIUM", expires);
+        purchaseMapper.insert(IapPurchase.builder()
+                .memberId(memberId).platform(platform).productId(req.getProductId())
+                .purchaseToken(token).orderId(req.getOrderId())
+                .status("VERIFIED").expiresAt(expires).build());
+        authService.syncSessionPlan(sessionToken, "PREMIUM");
+
+        log.info("[billing] PREMIUM granted member={} product={} platform={} expires={}",
+                memberId, req.getProductId(), platform, expires);
+
+        member.setPlan("PREMIUM");
+        member.setPlanExpiresAt(expires);
+        return MembershipResponse.of(member);
+    }
+
+    private Member mustFind(Long memberId) {
+        Member m = memberMapper.findById(memberId);
+        if (m == null) {
+            throw new ApiException(HttpStatus.NOT_FOUND, "회원을 찾을 수 없습니다.");
+        }
+        return m;
+    }
+}

src/main/java/com/sb/web/billing/GooglePlayVerifier.java

@@ -0,0 +1,11 @@
+package com.sb.web.billing;
+
+/**
+ * Google Play 구매 토큰 검증 추상화.
+ * 실연동(androidpublisher API + 서비스 계정) 구현체로 교체하면 된다.
+ */
+public interface GooglePlayVerifier {
+
+    /** 구매 토큰이 유효하면 true. 검증 미구성/실패 시 예외 또는 false. */
+    boolean verify(String productId, String purchaseToken);
+}

src/main/java/com/sb/web/billing/PremiumExpiryScheduler.java

@@ -0,0 +1,27 @@
+package com.sb.web.billing;
+
+import com.sb.web.auth.mapper.MemberMapper;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Component;
+
+/**
+ * 만료된 유료 멤버십 자동 강등. 매시간 실행.
+ * (만료일이 NULL 인 관리자 영구 부여는 강등되지 않음)
+ */
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class PremiumExpiryScheduler {
+
+    private final MemberMapper memberMapper;
+
+    @Scheduled(cron = "0 5 * * * *") // 매시 5분
+    public void downgradeExpired() {
+        int n = memberMapper.downgradeExpired();
+        if (n > 0) {
+            log.info("[billing] 만료 멤버십 강등: {}건", n);
+        }
+    }
+}

src/main/java/com/sb/web/billing/StubGooglePlayVerifier.java

@@ -0,0 +1,19 @@
+package com.sb.web.billing;
+
+import com.sb.web.common.exception.ApiException;
+import org.springframework.http.HttpStatus;
+import org.springframework.stereotype.Component;
+
+/**
+ * 실연동 전 스텁. 실제 Google Play 검증은 아직 구성되지 않았다.
+ * (테스트 모드에서는 BillingService 가 이 검증을 건너뛴다.)
+ */
+@Component
+public class StubGooglePlayVerifier implements GooglePlayVerifier {
+
+    @Override
+    public boolean verify(String productId, String purchaseToken) {
+        throw new ApiException(HttpStatus.SERVICE_UNAVAILABLE,
+                "구글 결제 검증이 아직 구성되지 않았습니다. (테스트 모드로만 결제 가능)");
+    }
+}

src/main/java/com/sb/web/billing/domain/IapPurchase.java

@@ -0,0 +1,28 @@
+package com.sb.web.billing.domain;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.time.LocalDateTime;
+
+/**
+ * 인앱 결제 기록 (iap_purchase).
+ */
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class IapPurchase {
+
+    private Long id;
+    private Long memberId;
+    private String platform;       // GOOGLE_PLAY / TEST
+    private String productId;
+    private String purchaseToken;
+    private String orderId;
+    private String status;         // VERIFIED / FAILED
+    private LocalDateTime expiresAt;
+    private LocalDateTime createdAt;
+}

src/main/java/com/sb/web/billing/dto/MembershipResponse.java

@@ -0,0 +1,24 @@
+package com.sb.web.billing.dto;
+
+import com.sb.web.auth.domain.Member;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+import java.time.LocalDateTime;
+
+/**
+ * 결제 후 멤버십 상태.
+ */
+@Data
+@AllArgsConstructor
+public class MembershipResponse {
+
+    private String plan;                 // FREE / PREMIUM
+    private LocalDateTime planExpiresAt;  // 만료일 (NULL=만료없음)
+    private boolean premium;
+
+    public static MembershipResponse of(Member m) {
+        boolean premium = "PREMIUM".equals(m.getPlan());
+        return new MembershipResponse(m.getPlan(), m.getPlanExpiresAt(), premium);
+    }
+}

src/main/java/com/sb/web/billing/dto/ProductResponse.java

@@ -0,0 +1,17 @@
+package com.sb.web.billing.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+/**
+ * 구독 상품 (업그레이드 화면 표시용).
+ */
+@Data
+@AllArgsConstructor
+public class ProductResponse {
+
+    private String id;       // Google Play 상품 ID
+    private String label;    // 표시 이름
+    private int months;      // 부여 개월수
+    private int priceKrw;    // 표시용 가격(원) — 실제 결제 금액은 Play Console 기준(스캐폴드 표시용)
+}

src/main/java/com/sb/web/billing/dto/VerifyRequest.java

@@ -0,0 +1,20 @@
+package com.sb.web.billing.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import lombok.Data;
+
+/**
+ * Google Play 구매 검증 요청.
+ */
+@Data
+public class VerifyRequest {
+
+    @NotBlank
+    private String productId;
+
+    /** Play 구매 토큰 (테스트는 'test-' 로 시작) */
+    @NotBlank
+    private String purchaseToken;
+
+    private String orderId;
+}

src/main/java/com/sb/web/billing/mapper/IapPurchaseMapper.java

@@ -0,0 +1,17 @@
+package com.sb.web.billing.mapper;
+
+import com.sb.web.billing.domain.IapPurchase;
+import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
+
+/**
+ * 인앱 결제 기록 매퍼.
+ */
+@Mapper
+public interface IapPurchaseMapper {
+
+    int insert(IapPurchase purchase);
+
+    /** 구매 토큰으로 기존 처리 여부 조회 (중복 결제 방지) */
+    IapPurchase findByToken(@Param("purchaseToken") String purchaseToken);
+}

src/main/java/com/sb/web/common/config/WebConfig.java

@@ -28,7 +28,7 @@ public class WebConfig implements WebMvcConfigurer {
                 .addPathPatterns("/api/auth/me", "/api/auth/points", "/api/auth/point-history",
                         "/api/auth/logout", "/api/auth/password",
                         "/api/auth/verify-password", "/api/auth/profile", "/api/auth/profile-image",
-                        "/api/board/**", "/api/admin/**", "/api/account/**");
+                        "/api/board/**", "/api/admin/**", "/api/account/**", "/api/billing/**");
         // 인가: 관리자 전용 경로 (authInterceptor 다음에 실행되어 role 검사)
         registry.addInterceptor(adminInterceptor)
                 .addPathPatterns("/api/admin/**");

src/main/resources/db/member.sql

@@ -38,6 +38,25 @@ ALTER TABLE member ADD COLUMN IF NOT EXISTS profile_image MEDIUMTEXT NULL COMMEN
 -- 포인트(게시판 글/댓글 작성 보상). 기존 회원은 0 으로 시작 (멱등).
 ALTER TABLE member ADD COLUMN IF NOT EXISTS points BIGINT NOT NULL DEFAULT 0 COMMENT '활동 포인트' AFTER plan;
 
+-- 멤버십 만료일 (유료 구독). NULL = 만료 없음(관리자 영구 부여) 또는 무료. 만료 지나면 스케줄러가 FREE 로 강등.
+ALTER TABLE member ADD COLUMN IF NOT EXISTS plan_expires_at DATETIME NULL COMMENT '유료 멤버십 만료일시' AFTER plan;
+
+-- 인앱 결제 기록 (영수증 검증·중복 방지·감사)
+CREATE TABLE IF NOT EXISTS iap_purchase (
+    id             BIGINT       NOT NULL AUTO_INCREMENT,
+    member_id      BIGINT       NOT NULL,
+    platform       VARCHAR(20)  NOT NULL COMMENT 'GOOGLE_PLAY / TEST',
+    product_id     VARCHAR(100) NOT NULL COMMENT '상품 ID(premium_monthly 등)',
+    purchase_token VARCHAR(512) NOT NULL COMMENT 'Play 구매 토큰(또는 테스트 토큰)',
+    order_id       VARCHAR(120) NULL,
+    status         VARCHAR(20)  NOT NULL COMMENT 'VERIFIED / FAILED',
+    expires_at     DATETIME     NULL COMMENT '이 결제로 부여된 만료일',
+    created_at     DATETIME     NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    PRIMARY KEY (id),
+    UNIQUE KEY uk_iap_token (purchase_token),
+    KEY idx_iap_member (member_id)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
 -- 포인트 적립/차감 이력 (감사 + 일일 지급 한도 계산용).
 CREATE TABLE IF NOT EXISTS point_history (
     id         BIGINT      NOT NULL AUTO_INCREMENT,

src/main/resources/mapper/AuthSessionMapper.xml

@@ -27,6 +27,10 @@
         UPDATE auth_session SET name = #{name} WHERE token = #{token}
     </update>
 
+    <update id="updatePlan">
+        UPDATE auth_session SET plan = #{plan} WHERE token = #{token}
+    </update>
+
     <delete id="delete">
         DELETE FROM auth_session WHERE token = #{token}
     </delete>

src/main/resources/mapper/IapPurchaseMapper.xml

@@ -0,0 +1,29 @@
+<?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.billing.mapper.IapPurchaseMapper">
+
+    <resultMap id="iapResultMap" type="com.sb.web.billing.domain.IapPurchase">
+        <id property="id" column="id"/>
+        <result property="memberId" column="member_id"/>
+        <result property="platform" column="platform"/>
+        <result property="productId" column="product_id"/>
+        <result property="purchaseToken" column="purchase_token"/>
+        <result property="orderId" column="order_id"/>
+        <result property="status" column="status"/>
+        <result property="expiresAt" column="expires_at"/>
+        <result property="createdAt" column="created_at"/>
+    </resultMap>
+
+    <insert id="insert" parameterType="com.sb.web.billing.domain.IapPurchase"
+            useGeneratedKeys="true" keyProperty="id">
+        INSERT INTO iap_purchase (member_id, platform, product_id, purchase_token, order_id, status, expires_at, created_at)
+        VALUES (#{memberId}, #{platform}, #{productId}, #{purchaseToken}, #{orderId}, #{status}, #{expiresAt}, NOW())
+    </insert>
+
+    <select id="findByToken" resultMap="iapResultMap">
+        SELECT id, member_id, platform, product_id, purchase_token, order_id, status, expires_at, created_at
+        FROM iap_purchase WHERE purchase_token = #{purchaseToken}
+    </select>
+
+</mapper>

src/main/resources/mapper/MemberMapper.xml

@@ -16,6 +16,7 @@
         <result property="profileImage" column="profile_image"/>
         <result property="role" column="role"/>
         <result property="plan" column="plan"/>
+        <result property="planExpiresAt" column="plan_expires_at"/>
         <result property="points" column="points"/>
         <result property="status" column="status"/>
         <result property="createdAt" column="created_at"/>
@@ -23,7 +24,7 @@
     </resultMap>
 
     <sql id="columns">
-        id, login_id, password, name, email, provider, provider_id, google_id, google_picture, profile_image, role, plan, points, status, created_at, updated_at
+        id, login_id, password, name, email, provider, provider_id, google_id, google_picture, profile_image, role, plan, plan_expires_at, points, status, created_at, updated_at
     </sql>
 
     <select id="findById" parameterType="long" resultMap="memberResultMap">
@@ -96,8 +97,20 @@
         UPDATE member SET role = #{role}, updated_at = NOW() WHERE id = #{id}
     </update>
 
+    <!-- 관리자 수동 변경: 만료일 없이(영구) 설정/해제 -->
     <update id="updatePlan">
-        UPDATE member SET plan = #{plan}, updated_at = NOW() WHERE id = #{id}
+        UPDATE member SET plan = #{plan}, plan_expires_at = NULL, updated_at = NOW() WHERE id = #{id}
+    </update>
+
+    <!-- 결제로 멤버십 부여/갱신: plan + 만료일 -->
+    <update id="updateMembership">
+        UPDATE member SET plan = #{plan}, plan_expires_at = #{expiresAt}, updated_at = NOW() WHERE id = #{id}
+    </update>
+
+    <!-- 만료된 유료회원 자동 강등 (스케줄러) -->
+    <update id="downgradeExpired">
+        UPDATE member SET plan = 'FREE', updated_at = NOW()
+        WHERE plan = 'PREMIUM' AND plan_expires_at IS NOT NULL AND plan_expires_at &lt; NOW()
     </update>
 
     <update id="updateStatus">