已完成“成绩管理与学业档案”模块：

教师批量录入平时、期中、期末成绩。
自动计算总评、绩点和及格状态。
支持缺考、缓考、免修。
教师提交 → 学院审核/退回 → 校级发布。
学生只能查看正式发布成绩。
自动统计平均分、完成度、及格率和加权 GPA。
SQLite 本地增量升级和 MySQL 正式迁移均已完成。
分级权限在前后端同时校验。

src/Jiaowu.Api/Domain/Academic/GradeEntities.cs

@@ -0,0 +1,50 @@
+using Jiaowu.Api.Domain.Common;
+
+namespace Jiaowu.Api.Domain.Academic;
+
+public sealed class GradeSheet : EntityBase
+{
+    public Guid TeachingTaskId { get; set; }
+    public TeachingTask? TeachingTask { get; set; }
+    public decimal RegularWeight { get; set; } = 30;
+    public decimal MidtermWeight { get; set; }
+    public decimal FinalWeight { get; set; } = 70;
+    public GradeSheetStatus Status { get; set; } = GradeSheetStatus.Draft;
+    public string? ReviewComment { get; set; }
+    public DateTime? SubmittedAt { get; set; }
+    public DateTime? ReviewedAt { get; set; }
+    public DateTime? PublishedAt { get; set; }
+    public ICollection<GradeRecord> Records { get; set; } = [];
+}
+
+public sealed class GradeRecord : EntityBase
+{
+    public Guid GradeSheetId { get; set; }
+    public GradeSheet? GradeSheet { get; set; }
+    public Guid StudentId { get; set; }
+    public Student? Student { get; set; }
+    public decimal? RegularScore { get; set; }
+    public decimal? MidtermScore { get; set; }
+    public decimal? FinalScore { get; set; }
+    public decimal? TotalScore { get; set; }
+    public decimal? GradePoint { get; set; }
+    public GradeExamStatus ExamStatus { get; set; } = GradeExamStatus.Normal;
+    public string? Notes { get; set; }
+}
+
+public enum GradeSheetStatus
+{
+    Draft = 1,
+    Submitted = 2,
+    Approved = 3,
+    Published = 4,
+    Returned = 5
+}
+
+public enum GradeExamStatus
+{
+    Normal = 1,
+    Absent = 2,
+    Deferred = 3,
+    Exempt = 4
+}