已按“实验成绩独立管理”完成修改。

每个实验项目独立建成绩单，支持评分项、参与状态、补做次数、安全违规、报告地址和教师评语。
流程为：录入 → 学院审核 → 教务发布；学生只能查看已发布成绩。
自主预约实验支持同步有效预约名单，已评分记录不会被误删。
课程成绩可将已发布实验成绩汇总为快照导入指定分项；导入后锁定，不能手工篡改。
实验项目成绩不完整时，对应课程分项保持空白，不按 0 分处理。
一级“实验管理”菜单下增加“项目与场次”“实验成绩”；学生端增加“实验安排”“实验成绩”。
已生成 MySQL 正式迁移及 SQLite 开发迁移，尚未操作生产数据库。
界面采用“实验项目 → 独立评分 → 审核发布”工作台设计。

src/Jiaowu.Api/Infrastructure/Grades/ExperimentGradeAggregationService.cs

@@ -0,0 +1,88 @@
+using Jiaowu.Api.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore;
+
+namespace Jiaowu.Api.Infrastructure.Grades;
+
+public static class ExperimentGradeAggregationService
+{
+    public static async Task<ExperimentGradeAggregateResult> CalculateAsync(
+        AppDbContext db,
+        Guid teachingTaskId,
+        IReadOnlyCollection<Guid> studentIds,
+        CancellationToken cancellationToken)
+    {
+        var sheets = await db.ExperimentGradeSheets.AsNoTracking()
+            .Where(x =>
+                x.Status ==
+                    Domain.Academic.ExperimentGradeSheetStatus.Published &&
+                x.ExperimentProject!.TeachingTaskId == teachingTaskId)
+            .OrderBy(x => x.ExperimentProject!.Code)
+            .Select(x => new PublishedExperimentSheet(
+                x.Id,
+                x.ExperimentProject!.Code,
+                x.ExperimentProject.Name,
+                x.ContributionWeight,
+                x.Records.Select(record => new PublishedExperimentScore(
+                    record.StudentId,
+                    record.TotalScore)).ToList()))
+            .AsSplitQuery()
+            .ToListAsync(cancellationToken);
+
+        var scores = new Dictionary<Guid, decimal?>();
+        foreach (var studentId in studentIds.Distinct())
+        {
+            decimal weightedTotal = 0;
+            decimal totalWeight = 0;
+            var complete = sheets.Count > 0;
+            foreach (var sheet in sheets)
+            {
+                var score = sheet.Scores.FirstOrDefault(x =>
+                    x.StudentId == studentId);
+                if (score?.TotalScore is not decimal totalScore)
+                {
+                    complete = false;
+                    break;
+                }
+                weightedTotal += totalScore * sheet.ContributionWeight;
+                totalWeight += sheet.ContributionWeight;
+            }
+            scores[studentId] = complete && totalWeight > 0
+                ? Math.Round(
+                    weightedTotal / totalWeight,
+                    1,
+                    MidpointRounding.AwayFromZero)
+                : null;
+        }
+
+        return new ExperimentGradeAggregateResult(
+            sheets.Count,
+            sheets.Select(x => new ExperimentGradeAggregateProject(
+                x.Id,
+                x.Code,
+                x.Name,
+                x.ContributionWeight)).ToList(),
+            scores);
+    }
+
+    private sealed record PublishedExperimentSheet(
+        Guid Id,
+        string Code,
+        string Name,
+        decimal ContributionWeight,
+        List<PublishedExperimentScore> Scores);
+
+    private sealed record PublishedExperimentScore(
+        Guid StudentId,
+        decimal? TotalScore);
+}
+
+public sealed record ExperimentGradeAggregateResult(
+    int PublishedProjectCount,
+    IReadOnlyList<ExperimentGradeAggregateProject> Projects,
+    IReadOnlyDictionary<Guid, decimal?> Scores);
+
+public sealed record ExperimentGradeAggregateProject(
+    Guid Id,
+    string Code,
+    string Name,
+    decimal ContributionWeight);

src/Jiaowu.Api/Infrastructure/Grades/ExperimentGradeCalculator.cs

@@ -0,0 +1,45 @@
+using Jiaowu.Api.Domain.Academic;
+
+namespace Jiaowu.Api.Infrastructure.Grades;
+
+public static class ExperimentGradeCalculator
+{
+    public static bool AreWeightsValid(
+        decimal contributionWeight,
+        decimal passScore,
+        IEnumerable<ExperimentGradeItem> items)
+    {
+        var itemList = items.ToList();
+        return contributionWeight is > 0 and <= 100 &&
+               passScore is >= 0 and <= 100 &&
+               itemList.Count > 0 &&
+               itemList.All(item => item.Weight is > 0 and <= 100) &&
+               itemList.Sum(item => item.Weight) == 100;
+    }
+
+    public static decimal? CalculateTotal(
+        ExperimentGradeRecord record,
+        IReadOnlyCollection<ExperimentGradeItem> items)
+    {
+        if (record.SafetyViolation ||
+            record.ParticipationStatus == ExperimentParticipationStatus.Absent)
+            return 0;
+        if (record.ParticipationStatus is
+            ExperimentParticipationStatus.Pending or
+            ExperimentParticipationStatus.Excused or
+            ExperimentParticipationStatus.Exempt)
+            return null;
+
+        var scores = record.ItemScores.ToDictionary(
+            x => x.ExperimentGradeItemId);
+        decimal total = 0;
+        foreach (var item in items)
+        {
+            if (!scores.TryGetValue(item.Id, out var score) ||
+                !score.Score.HasValue)
+                return null;
+            total += score.Score.Value * item.Weight / 100;
+        }
+        return Math.Round(total, 1, MidpointRounding.AwayFromZero);
+    }
+}