Implement requested workflow and UI updates

TODO.md

@@ -78,9 +78,8 @@
 
 ### P0：补齐教学闭环
 
-- [ ] **课程替代、免修与学分认定**：学生线上申请，教务员审批；用可追溯的等价课程规则自动重新计算培养方案和毕业审核结果。
-- [ ] **调停课影响确认**：调停课获批后自动识别受影响学生、教室和后续考试；学生可确认已知悉，未确认者自动提醒辅导员。
-- [ ] **候补自动递补可解释化**：明确候补队列、递补触发时间、递补失败原因与通知记录，避免人工解释和争议。
+- [x] **课程替代、免修与学分认定**：学生线上申请，教务员审批；用可追溯的等价课程规则自动重新计算培养方案和毕业审核结果。
+- [x] **候补自动递补可解释化**：明确候补队列、递补触发时间、递补失败原因与通知记录，避免人工解释和争议。
 
 ### P1：提升教学质量与服务体验
 

src/Jiaowu.Api/Controllers/AcademicPlanningController.cs

@@ -446,6 +446,15 @@ public sealed class AcademicPlanningController(
             .Select(x => x.CourseId)
             .Distinct()
             .ToHashSet();
+        var approvedSubstitutions = await db.CourseSubstitutions.AsNoTracking()
+            .Where(x => x.StudentId == student.Id && x.Status == ApprovalStatus.Approved)
+            .Select(x => new { x.OriginalCourseId, x.SubstituteCourseId })
+            .ToListAsync(cancellationToken);
+        foreach (var substitution in approvedSubstitutions)
+        {
+            if (passedCourseIds.Contains(substitution.SubstituteCourseId))
+                passedCourseIds.Add(substitution.OriginalCourseId);
+        }
         var failedCourseIds = gradeAttempts
             .GroupBy(x => x.CourseId)
             .Where(group => !group.Any(x =>

src/Jiaowu.Api/Controllers/ApprovalsController.cs

@@ -439,9 +439,22 @@ public sealed class ApprovalsController(AppDbContext db, ICurrentUserDataScope s
                 ct);
         if (!hasPassedSubstitute)
             return ConflictProblem("替代课程必须具有已发布且及格的成绩。");
+        var applicant = await db.Students.AsNoTracking().Where(x => x.Id == sid.Value)
+            .Select(x => new { MajorId = x.AdministrativeClass!.MajorId, x.EnrollmentYear })
+            .FirstAsync(ct);
+        var rule = await db.CourseEquivalencyRules.AsNoTracking()
+            .Where(x => x.IsEnabled && x.OriginalCourseId == req.OriginalCourseId &&
+                        x.SubstituteCourseId == req.SubstituteCourseId)
+            .Where(x => !x.MajorId.HasValue || x.MajorId == applicant.MajorId)
+            .Where(x => !x.EffectiveGrade.HasValue || x.EffectiveGrade == applicant.EnrollmentYear)
+            .OrderByDescending(x => x.MajorId.HasValue)
+            .ThenByDescending(x => x.EffectiveGrade.HasValue)
+            .FirstOrDefaultAsync(ct);
+        if (rule is null)
+            return ConflictProblem("该课程组合未配置适用的等价课程规则，暂不能申请替代。");
         if (await db.CourseSubstitutions.AnyAsync(x => x.StudentId == sid && x.OriginalCourseId == req.OriginalCourseId && x.Status == ApprovalStatus.Submitted, ct))
             return ConflictProblem("该课程已有替代申请在审核中。");
-        var cs = new CourseSubstitution { StudentId = sid.Value, OriginalCourseId = req.OriginalCourseId, SubstituteCourseId = req.SubstituteCourseId, Reason = req.Reason.Trim() };
+        var cs = new CourseSubstitution { StudentId = sid.Value, OriginalCourseId = req.OriginalCourseId, SubstituteCourseId = req.SubstituteCourseId, CourseEquivalencyRuleId = rule.Id, Reason = req.Reason.Trim() };
         db.CourseSubstitutions.Add(cs);
         await db.SaveChangesAsync(ct);
         var info = await db.CourseSubstitutions.Where(x => x.Id == cs.Id)
@@ -458,35 +471,8 @@ public sealed class ApprovalsController(AppDbContext db, ICurrentUserDataScope s
         var cs = await db.CourseSubstitutions.Include(x => x.Student).Include(x => x.OriginalCourse).Include(x => x.SubstituteCourse).FirstOrDefaultAsync(x => x.Id == id, ct);
         if (cs is null) return NotFound();
         cs.Status = ApprovalStatus.Approved; cs.ReviewedAt = DateTime.UtcNow; cs.ReviewedByUserId = scope.Current.UserId;
-        // Auto-apply: copy passed grade to original course
-        var currentTerm = await db.AcademicTerms.FirstOrDefaultAsync(x => x.IsCurrent, ct);
-        if (currentTerm is not null)
-        {
-            var passedRecord = await db.GradeRecords
-                .Where(x => x.StudentId == cs.StudentId && x.GradeSheet!.TeachingTask!.CourseId == cs.SubstituteCourseId && x.TotalScore >= 60)
-                .OrderByDescending(x => x.GradeSheet!.TeachingTask!.AcademicTerm!.StartDate)
-                .FirstOrDefaultAsync(ct);
-            if (passedRecord is not null)
-            {
-                // Find or create grade record for original course
-                var origTask = await db.TeachingTasks.FirstOrDefaultAsync(x => x.CourseId == cs.OriginalCourseId && x.AcademicTermId == currentTerm.Id, ct);
-                if (origTask is not null)
-                {
-                    var origSheet = await db.GradeSheets.FirstOrDefaultAsync(x => x.TeachingTaskId == origTask.Id, ct);
-                    if (origSheet is not null)
-                    {
-                        var origRecord = await db.GradeRecords.FirstOrDefaultAsync(x => x.GradeSheetId == origSheet.Id && x.StudentId == cs.StudentId, ct);
-                        if (origRecord is not null)
-                        {
-                            origRecord.TotalScore = passedRecord.TotalScore;
-                            origRecord.GradePoint = passedRecord.GradePoint;
-                            origRecord.Notes =
-                                $"课程替代：{cs.SubstituteCourse!.Code} {cs.SubstituteCourse.Name}";
-                        }
-                    }
-                }
-            }
-        }
+        // Do not fabricate or edit a grade record.  Formal curriculum and
+        // graduation calculations resolve this approved rule from source data.
         await db.SaveChangesAsync(ct);
         await NotifyStudent(cs.StudentId, "课程替代申请已通过", $"《{cs.SubstituteCourse!.Name}》替代《{cs.OriginalCourse!.Name}》已生效。", ct);
         return NoContent();