重构项目结构，移除Assignment相关功能，优化Submission模块

Entities/DTO/User/StudentExamDetailDto.cs

@@ -0,0 +1,21 @@
+using Entities.Contracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Entities.DTO
+{
+    public record StudentExamDetailDto
+    {
+        public Guid Id { get; init; }
+        public string? DisplayName { get; init; }
+
+        public uint ErrorQuestionNum { get; init; }
+        public Dictionary<string, uint> ErrorQuestionTypes { get; init; } = new Dictionary<string, uint>();	
+        public Dictionary<SubjectAreaEnum, uint> SubjectAreaErrorQuestionDis { get; init; } = new Dictionary<SubjectAreaEnum, uint>();	
+        public Dictionary<byte, uint> LessonErrorDis { get; init; } = new Dictionary<byte, uint>();	
+        public float Score { get; init; }
+    }
+}

Entities/DTO/User/UserClassInfoDto.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Entities.DTO
+{
+	public record UserClassDetailInfoDto(IEnumerable<UserClassInfoDto> UserClassInfos, string School);
+	public record UserClassInfoDto(Guid Id, byte Class, byte Grade);
+}

Entities/DTO/User/UserDto.cs

@@ -0,0 +1,129 @@
+using Entities.Contracts;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Entities.DTO
+{
+    /// <summary>
+    /// 用户信息数据传输对象
+    /// 用于在API调用中传输用户的基本信息
+    /// </summary>
+    public record UserDto
+    {
+        /// <summary>
+        /// 用户唯一标识符
+        /// </summary>
+        public Guid Id { get; init; }
+
+        /// <summary>
+        /// 用户名
+        /// </summary>
+        public string? UserName { get; init; }
+
+        /// <summary>
+        /// 电子邮箱
+        /// </summary>
+        [EmailAddress]
+        public string? Email { get; init; }
+
+        /// <summary>
+        /// 手机号码
+        /// </summary>
+        [Phone]
+        public string? PhoneNumber { get; init; }
+
+        /// <summary>
+        /// 显示名称
+        /// </summary>
+        public string? DisplayName { get; init; }
+
+        /// <summary>
+        /// 家庭住址
+        /// </summary>
+        public string? HomeAddress { get; init; }
+
+        /// <summary>
+        /// 用户角色
+        /// </summary>
+        public UserRoles? Role { get; init; }
+
+        /// <summary>
+        /// 教授科目ID
+        /// </summary>
+        public Guid? TeachSubjectId { get; init; }
+
+        /// <summary>
+        /// 教授科目信息
+        /// </summary>
+        public SubjectDto? TeachSubject { get; init; }
+
+        /// <summary>
+        /// 用户加入的班级数量
+        /// </summary>
+        public int JoinedClassCount { get; init; }
+
+        /// <summary>
+        /// 创建的问题数量
+        /// </summary>
+        public int CreatedQuestionsCount { get; init; }
+
+        /// <summary>
+        /// 创建的考试数量
+        /// </summary>
+        public int CreatedExamsCount { get; init; }
+
+        /// <summary>
+        /// 提交的作业数量
+        /// </summary>
+        public int SubmittedAssignmentsCount { get; init; }
+
+        /// <summary>
+        /// 批改的作业数量
+        /// </summary>
+        public int GradedAssignmentsCount { get; init; }
+
+        /// <summary>
+        /// 用户创建时间
+        /// </summary>
+        public DateTime CreatedAt { get; init; }
+
+        /// <summary>
+        /// 用户最后更新时间
+        /// </summary>
+        public DateTime UpdatedAt { get; init; }
+
+        /// <summary>
+        /// 用户是否已验证邮箱
+        /// </summary>
+        public bool EmailConfirmed { get; init; }
+
+        /// <summary>
+        /// 用户是否已锁定
+        /// </summary>
+        public bool LockoutEnabled { get; init; }
+
+        /// <summary>
+        /// 用户锁定结束时间
+        /// </summary>
+        public DateTime? LockoutEnd { get; init; }
+
+        /// <summary>
+        /// 获取用户角色的显示名称
+        /// </summary>
+        public string? RoleDisplayName => Role?.GetDisplayName();
+
+        /// <summary>
+        /// 获取用户角色的简短名称
+        /// </summary>
+        public string? RoleShortName => Role?.GetShortName();
+
+        /// <summary>
+        /// 获取用户的基本信息字符串
+        /// </summary>
+        public string? UserInfoString => $"{DisplayName ?? UserName} ({Email})";
+    }
+}

Entities/DTO/User/UserForAdmin.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Entities.DTO
+{
+	public record UserForAdmin
+	{
+		public string Email { get; init; }
+		public string SchoolName { get; init; }
+		public string Password { get; init; }
+		public string DisplayName { get; init; }
+		public string Address { get; init; }
+	}
+}

Entities/DTO/User/UserForRegistrationDto.cs

@@ -0,0 +1,43 @@
+using Entities.Contracts;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Entities.DTO
+{
+    public class UserForRegistrationDto
+    {
+        [Required(ErrorMessage = "姓名是必填项。")]
+        [StringLength(50, MinimumLength = 2, ErrorMessage = "姓名长度必须在 2 到 50 个字符之间。")]
+        public  string DisplayName { get; set; }
+
+        [Required(ErrorMessage = "电子邮件是必填项。")]
+        [EmailAddress(ErrorMessage = "电子邮件格式不正确。")]
+        public  string Email { get; set; }
+
+        [Required(ErrorMessage = "密码是必填项。")]
+        [StringLength(100, MinimumLength = 6, ErrorMessage = "密码长度至少为 6 个字符。")]
+        [RegularExpression(@"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&.])[A-Za-z\d@$!%*?&.]{6,}$",
+         ErrorMessage = "密码必须包含至少一个大写字母、一个小写字母、一个数字和一个特殊字符。特殊字符包含 @$!%*?&. ")]
+        public  string Password { get; set; }
+
+        [Compare(nameof(Password), ErrorMessage = "密码和确认密码不匹配。")]
+        [Required(ErrorMessage = "确认密码是必填项。")]
+        public  string ConfirmPassword { get; set; }
+
+        [Required(ErrorMessage = "至少选择一个角色。")]
+        public UserRoles Roles { get; set; } = UserRoles.Student;
+
+        [Phone(ErrorMessage = "电话号码格式不正确。")]
+        [StringLength(11, MinimumLength = 11, ErrorMessage = "电话号码必须是 11 位数字。")]
+        public string? PhoneNumber { get; set; }
+
+        [StringLength(200, ErrorMessage = "家庭住址不能超过 200 个字符。")]
+        public string? HomeAddress { get; set; }
+
+        public RegisterUserToClassDto RegisterUserToClassDto { get; set; } = new RegisterUserToClassDto();
+    }
+}

Entities/DTO/User/UserListDto.cs

@@ -0,0 +1,11 @@
+using Entities.Contracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Entities.DTO
+{
+	public record UserListDto (Guid Id, string DisplayName, UserRoles Role, string Email, SubjectDto TeachSubject);
+}

Entities/DTO/User/UserRegistrationToClassDto.cs

@@ -0,0 +1,18 @@
+using Entities.Contracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Entities.DTO
+{
+    public class UserRegistrationToClassDto
+    {
+        public string User { get; set; } = string.Empty;
+        public byte ClassId { get; set; }
+        public byte GradeId { get; set; }
+        public UserRoles Roles { get; set; } = UserRoles.Student;
+        public SubjectAreaEnum SubjectArea { get; set; } = SubjectAreaEnum.Unknown;
+    }
+}