feat(coupon): 添加优惠券领取功能

- 新增 CouponClaimRequest 和 CouponClaimResult 类用于处理优惠券领取请求和结果
- 在 ICouponService 接口中添加 claimCoupon 方法
- 在 CouponServiceImpl 中实现 claimCoupon 方法，包括参数验证、优惠券查询、库存检查、记录创建等步骤
- 优化日志记录和异常处理

src/main/java/com/ycwl/basic/pricing/dto/CouponClaimRequest.java

@@ -0,0 +1,51 @@
+package com.ycwl.basic.pricing.dto;
+
+import lombok.Data;
+
+/**
+ * 优惠券领取请求DTO
+ */
+@Data
+public class CouponClaimRequest {
+    
+    /**
+     * 用户ID
+     */
+    private Long userId;
+    
+    /**
+     * 优惠券ID
+     */
+    private Long couponId;
+    
+    /**
+     * 景区ID（可选，记录在哪个景区领取）
+     */
+    private String scenicId;
+    
+    /**
+     * 领取来源（可选，如：活动页面、签到奖励等）
+     */
+    private String claimSource;
+    
+    public CouponClaimRequest() {
+    }
+    
+    public CouponClaimRequest(Long userId, Long couponId) {
+        this.userId = userId;
+        this.couponId = couponId;
+    }
+    
+    public CouponClaimRequest(Long userId, Long couponId, String scenicId) {
+        this.userId = userId;
+        this.couponId = couponId;
+        this.scenicId = scenicId;
+    }
+    
+    public CouponClaimRequest(Long userId, Long couponId, String scenicId, String claimSource) {
+        this.userId = userId;
+        this.couponId = couponId;
+        this.scenicId = scenicId;
+        this.claimSource = claimSource;
+    }
+}

src/main/java/com/ycwl/basic/pricing/dto/CouponClaimResult.java

@@ -0,0 +1,100 @@
+package com.ycwl.basic.pricing.dto;
+
+import com.ycwl.basic.pricing.entity.PriceCouponClaimRecord;
+import lombok.Data;
+
+import java.util.Date;
+
+/**
+ * 优惠券领取结果DTO
+ */
+@Data
+public class CouponClaimResult {
+    
+    /**
+     * 是否成功
+     */
+    private boolean success;
+    
+    /**
+     * 错误消息（失败时）
+     */
+    private String errorMessage;
+    
+    /**
+     * 错误码（失败时）
+     */
+    private String errorCode;
+    
+    /**
+     * 领取记录ID（成功时）
+     */
+    private Long claimRecordId;
+    
+    /**
+     * 优惠券ID
+     */
+    private Long couponId;
+    
+    /**
+     * 优惠券名称
+     */
+    private String couponName;
+    
+    /**
+     * 领取时间
+     */
+    private Date claimTime;
+    
+    /**
+     * 用户ID
+     */
+    private Long userId;
+    
+    /**
+     * 景区ID
+     */
+    private String scenicId;
+    
+    /**
+     * 创建成功结果
+     */
+    public static CouponClaimResult success(PriceCouponClaimRecord record, String couponName) {
+        CouponClaimResult result = new CouponClaimResult();
+        result.success = true;
+        result.claimRecordId = record.getId();
+        result.couponId = record.getCouponId();
+        result.couponName = couponName;
+        result.claimTime = record.getClaimTime();
+        result.userId = record.getUserId();
+        result.scenicId = record.getScenicId();
+        return result;
+    }
+    
+    /**
+     * 创建失败结果
+     */
+    public static CouponClaimResult failure(String errorCode, String errorMessage) {
+        CouponClaimResult result = new CouponClaimResult();
+        result.success = false;
+        result.errorCode = errorCode;
+        result.errorMessage = errorMessage;
+        return result;
+    }
+    
+    /**
+     * 创建失败结果（仅错误消息）
+     */
+    public static CouponClaimResult failure(String errorMessage) {
+        return failure("CLAIM_FAILED", errorMessage);
+    }
+    
+    // 常用错误码常量
+    public static final String ERROR_COUPON_NOT_FOUND = "COUPON_NOT_FOUND";
+    public static final String ERROR_COUPON_EXPIRED = "COUPON_EXPIRED";
+    public static final String ERROR_COUPON_INACTIVE = "COUPON_INACTIVE";
+    public static final String ERROR_COUPON_OUT_OF_STOCK = "COUPON_OUT_OF_STOCK";
+    public static final String ERROR_ALREADY_CLAIMED = "ALREADY_CLAIMED";
+    public static final String ERROR_INVALID_PARAMS = "INVALID_PARAMS";
+    public static final String ERROR_SYSTEM_ERROR = "SYSTEM_ERROR";
+}