feat: 应用内通知系统 + 结构化手术史/用药等相关改动

- 新增用户通知 outbox 流水线(EfUserNotificationPipeline)与后台投递 worker
- 通知中心页面及前端通知服务接入
- 健康指标异常、用药/运动提醒等事件统一产出站内通知
- 健康档案结构化手术史、用药提醒扫描、医生/用户端点等配套调整
- AppDbContext 注册通知相关实体

backend/src/Health.Application/Medications/MedicationContracts.cs

@@ -78,7 +78,6 @@ public interface IMedicationRepository
     Task<bool> DoseLogExistsAsync(Guid userId, Guid medicationId, TimeOnly scheduledTime, DateTime startUtc, DateTime endUtc, CancellationToken ct);
     Task<MedicationLog?> GetDoseLogAsync(Guid userId, Guid medicationId, TimeOnly scheduledTime, DateTime startUtc, DateTime endUtc, CancellationToken ct);
     Task<IReadOnlyList<Medication>> ListActiveForReminderScanAsync(CancellationToken ct);
-    Task<bool> HasTakenInWindowAsync(Guid userId, Guid medicationId, DateTime startUtc, DateTime endUtc, CancellationToken ct);
     Task AddMedicationAsync(Medication medication, CancellationToken ct);
     Task AddLogAsync(MedicationLog log, CancellationToken ct);
     void DeleteMedication(Medication medication);

backend/src/Health.Application/Medications/MedicationReminderScanner.cs

@@ -21,10 +21,18 @@ public sealed class MedicationReminderScanner(IMedicationRepository medications)
         foreach (var medication in active)
         {
             if (!IsActiveOn(medication, date) || !GetDosesForToday(medication, date)) continue;
-            if (await _medications.HasTakenInWindowAsync(medication.UserId, medication.Id, todayStartUtc, todayEndUtc, ct)) continue;
 
             foreach (var scheduledTime in medication.TimeOfDay.Where(t => IsInWindow(t, windowStart, time)))
             {
+                if (await _medications.DoseLogExistsAsync(
+                    medication.UserId,
+                    medication.Id,
+                    scheduledTime,
+                    todayStartUtc,
+                    todayEndUtc,
+                    ct))
+                    continue;
+
                 tasks.Add(new MedicationReminderTask(
                     Guid.NewGuid(),
                     medication.UserId,