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/Infrastructure/Persistence/AppDbContext.cs

@@ -33,6 +33,8 @@ public sealed class AppDbContext(DbContextOptions<AppDbContext> options)
     public DbSet<CourseSelectionOffering> CourseSelectionOfferings =>
         Set<CourseSelectionOffering>();
     public DbSet<CourseEnrollment> CourseEnrollments => Set<CourseEnrollment>();
+    public DbSet<GradeSheet> GradeSheets => Set<GradeSheet>();
+    public DbSet<GradeRecord> GradeRecords => Set<GradeRecord>();
     public DbSet<AuditLog> AuditLogs => Set<AuditLog>();
 
     protected override void OnModelCreating(ModelBuilder builder)
@@ -317,6 +319,40 @@ public sealed class AppDbContext(DbContextOptions<AppDbContext> options)
                 .OnDelete(DeleteBehavior.Restrict);
         });
 
+        builder.Entity<GradeSheet>(entity =>
+        {
+            entity.Property(x => x.RegularWeight).HasPrecision(5, 1);
+            entity.Property(x => x.MidtermWeight).HasPrecision(5, 1);
+            entity.Property(x => x.FinalWeight).HasPrecision(5, 1);
+            entity.Property(x => x.ReviewComment).HasMaxLength(500);
+            entity.HasIndex(x => x.TeachingTaskId).IsUnique();
+            entity.HasIndex(x => x.Status);
+            entity.HasOne(x => x.TeachingTask)
+                .WithMany()
+                .HasForeignKey(x => x.TeachingTaskId)
+                .OnDelete(DeleteBehavior.Restrict);
+        });
+
+        builder.Entity<GradeRecord>(entity =>
+        {
+            entity.Property(x => x.RegularScore).HasPrecision(5, 1);
+            entity.Property(x => x.MidtermScore).HasPrecision(5, 1);
+            entity.Property(x => x.FinalScore).HasPrecision(5, 1);
+            entity.Property(x => x.TotalScore).HasPrecision(5, 1);
+            entity.Property(x => x.GradePoint).HasPrecision(3, 1);
+            entity.Property(x => x.Notes).HasMaxLength(300);
+            entity.HasIndex(x => new { x.GradeSheetId, x.StudentId }).IsUnique();
+            entity.HasIndex(x => new { x.StudentId, x.TotalScore });
+            entity.HasOne(x => x.GradeSheet)
+                .WithMany(x => x.Records)
+                .HasForeignKey(x => x.GradeSheetId)
+                .OnDelete(DeleteBehavior.Cascade);
+            entity.HasOne(x => x.Student)
+                .WithMany()
+                .HasForeignKey(x => x.StudentId)
+                .OnDelete(DeleteBehavior.Restrict);
+        });
+
         builder.Entity<AuditLog>(entity =>
         {
             entity.Property(x => x.Method).HasMaxLength(10);