refactor: 统一业务异常处理，标准化结果码和错误响应

1.  新增并完善ResultCode枚举，补充标准HTTP状态码对应的业务状态码
2.  重构BusinessException，新增基于ResultCode的构造函数和ThrowIf扩展方法
3.  替换所有硬编码的HTTP状态码为统一的ResultCode枚举
4.  优化全局异常中间件，根据业务状态码映射对应HTTP状态码并规范化JSON响应
5.  修复OssImageHelper和AutoDotCodeConsumer中的OSS文件处理逻辑
6.  新增用户答题快照实体类
7.  清理废弃的宠物模块迁移脚本

QYZH.InteractiveMagazine.Models/Entity/JournalPageTaskUserAnswerSnapshot.cs

@@ -0,0 +1,161 @@
+using SqlSugar;
+
+namespace QYZH.InteractiveMagazine.Models.Entity
+{
+    /// <summary>
+    /// Snapshot record for a user answer.
+    /// </summary>
+    [SugarTable("JournalPageTaskUserAnswerSnapshot")]
+    public class JournalPageTaskUserAnswerSnapshot : SqlSugarBaseEntity
+    {
+        /// <summary>
+        /// Source JournalPageTaskUserAnswer record Id.
+        /// </summary>
+        public long JournalPageTaskUserAnswerId { get; set; }
+
+        /// <summary>
+        /// Journal Id.
+        /// </summary>
+        public long JournalId { get; set; }
+
+        /// <summary>
+        /// Journal page Id.
+        /// </summary>
+        public long JournalPageId { get; set; }
+
+        /// <summary>
+        /// Journal page task Id.
+        /// </summary>
+        public long JournalPageTaskId { get; set; }
+
+        /// <summary>
+        /// Journal page task group Id.
+        /// </summary>
+        public long JournalPageTaskGroupId { get; set; }
+
+        /// <summary>
+        /// User Id.
+        /// </summary>
+        public long UserId { get; set; }
+
+        /// <summary>
+        /// Answer result.
+        /// </summary>
+        public string? Result { get; set; }
+
+        /// <summary>
+        /// Points awarded.
+        /// </summary>
+        public float Points { get; set; }
+
+        /// <summary>
+        /// Growth points awarded.
+        /// </summary>
+        public float GrowthPoints { get; set; }
+
+        /// <summary>
+        /// Task score.
+        /// </summary>
+        public float Score { get; set; }
+
+        /// <summary>
+        /// Question answer image URL.
+        /// </summary>
+        public string? QuestionAnswerUrl { get; set; }
+
+        /// <summary>
+        /// Answer image URL.
+        /// </summary>
+        public string? AnswerUrl { get; set; }
+
+        /// <summary>
+        /// Page answer image URL.
+        /// </summary>
+        public string? PageAnswerUrl { get; set; }
+
+        /// <summary>
+        /// Optimistic concurrency revision.
+        /// </summary>
+        public int Revision { get; set; }
+
+        /// <summary>
+        /// Answer status.
+        /// </summary>
+        public int AnswerStatus { get; set; }
+
+        /// <summary>
+        /// Answer start time.
+        /// </summary>
+        public DateTime AnswerStartTime { get; set; }
+
+        /// <summary>
+        /// Answer end time.
+        /// </summary>
+        public DateTime AnswerEndTime { get; set; }
+
+        /// <summary>
+        /// Answer duration in seconds.
+        /// </summary>
+        public int AnswerSeconds { get; set; }
+
+        /// <summary>
+        /// Image recognition result.
+        /// </summary>
+        public int ImageRecognition { get; set; }
+
+        /// <summary>
+        /// Journal page number.
+        /// </summary>
+        public int JournalPageNum { get; set; }
+
+        /// <summary>
+        /// Modify count.
+        /// </summary>
+        public int Modify { get; set; }
+
+        /// <summary>
+        /// Last tag Id.
+        /// </summary>
+        public long LastTag { get; set; }
+
+        /// <summary>
+        /// Dot page number.
+        /// </summary>
+        public int DotPageNum { get; set; }
+
+        /// <summary>
+        /// Page result image URL.
+        /// </summary>
+        public string? PageResultUrl { get; set; }
+
+        /// <summary>
+        /// Question type.
+        /// </summary>
+        public string? Type { get; set; }
+
+        /// <summary>
+        /// Dot page number text.
+        /// </summary>
+        public string? DotPageNo { get; set; }
+
+        /// <summary>
+        /// Page answer dot image URL.
+        /// </summary>
+        public string? PageAnswerDotUrl { get; set; }
+
+        /// <summary>
+        /// Break count.
+        /// </summary>
+        public int BreakCount { get; set; }
+
+        /// <summary>
+        /// Break time records.
+        /// </summary>
+        public string? BreakTimes { get; set; }
+
+        /// <summary>
+        /// Assignment status.
+        /// </summary>
+        public string? AssignmentStatus { get; set; }
+    }
+}