feat: 添加期刊二维码管理功能，调整UserJournal的UserId为可空类型

1.  新增数据库脚本修改User表UserId字段为可空
2.  新增期刊二维码CRUD接口与控制器
3.  重构绑定期刊逻辑，优化重复绑定校验
4.  删除冗余的JwtHelper重载方法

QYZH.InteractiveMagazine.WebApi/Controllers/UserJournalQrCodeController.cs

@@ -0,0 +1,63 @@
+using Microsoft.AspNetCore.Mvc;
+using QYZH.InteractiveMagazine.IService;
+using QYZH.InteractiveMagazine.Models.Dto;
+using QYZH.InteractiveMagazine.Models.Enum;
+
+namespace QYZH.InteractiveMagazine.WebApi.Controllers;
+
+/// <summary>
+/// 期刊二维码管理
+/// </summary>
+[ApiController]
+[ApiExplorerSettings(GroupName = nameof(ApiVersionEnum.Platform))]
+[Route("api/userJournalQrCode")]
+public class UserJournalQrCodeController(IUserJournalService userJournalService) : BaseController
+{
+    /// <summary>
+    /// 生成期刊二维码
+    /// </summary>
+    /// <param name="input">生成输入</param>
+    /// <returns>二维码记录</returns>
+    [HttpPost("add")]
+    public async Task<BaseResponse<UserJournalQrCodeOutput>> AddAsync([FromBody] CreateUserJournalQrCodeInput input)
+    {
+        var result = await userJournalService.CreateQrCodeAsync(input, GetCurrentUserId() ?? 0);
+        return BaseResponse<UserJournalQrCodeOutput>.Success(result);
+    }
+
+    /// <summary>
+    /// 分页查询期刊二维码
+    /// </summary>
+    /// <param name="input">查询条件</param>
+    /// <returns>分页结果</returns>
+    [HttpPost("pagelist")]
+    public async Task<BaseResponse<PageListModel<UserJournalQrCodeOutput>>> GetPageListAsync([FromBody] UserJournalQrCodeQueryInput input)
+    {
+        var result = await userJournalService.GetQrCodePageListAsync(input);
+        return BaseResponse<PageListModel<UserJournalQrCodeOutput>>.Success(result);
+    }
+
+    /// <summary>
+    /// 获取期刊二维码详情
+    /// </summary>
+    /// <param name="id">二维码记录Id</param>
+    /// <returns>二维码记录</returns>
+    [HttpGet("detail/{id:long}")]
+    public async Task<BaseResponse<UserJournalQrCodeOutput>> GetDetailAsync(long id)
+    {
+        var result = await userJournalService.GetQrCodeDetailAsync(id);
+        return BaseResponse<UserJournalQrCodeOutput>.Success(result);
+    }
+
+    /// <summary>
+    /// 删除未绑定的期刊二维码
+    /// </summary>
+    /// <param name="input">删除输入</param>
+    /// <returns>是否成功</returns>
+    [HttpPost("delete")]
+    public async Task<BaseResponse<bool>> DeleteAsync([FromBody] DeleteUserJournalQrCodeInput input)
+    {
+        var result = await userJournalService.DeleteQrCodeAsync(input, GetCurrentUserId() ?? 0);
+        return BaseResponse<bool>.Success(result);
+    }
+}