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/Notifications/InAppNotificationContracts.cs

@@ -5,22 +5,56 @@ public sealed record InAppNotificationDto(
     string Type,
     string Title,
     string Message,
+    string Severity,
+    string? ActionType,
+    string? ActionTargetId,
+    bool IsRead,
     DateTime CreatedAt);
 
+public sealed record NotificationMessage(
+    string Type,
+    string Title,
+    string Message,
+    string Severity,
+    string? ActionType,
+    string? ActionTargetId);
+
 public interface IInAppNotificationService
 {
     Task<IReadOnlyList<InAppNotificationDto>> GetPendingAsync(Guid userId, CancellationToken ct);
+    Task<IReadOnlyList<InAppNotificationDto>> GetHistoryAsync(Guid userId, CancellationToken ct);
     Task<bool> AcknowledgeAsync(Guid userId, Guid notificationId, CancellationToken ct);
+    Task<int> MarkAllReadAsync(Guid userId, CancellationToken ct);
+    Task<bool> DeleteAsync(Guid userId, Guid notificationId, CancellationToken ct);
 }
 
 public interface IInAppNotificationRepository
 {
     Task<IReadOnlyList<InAppNotificationRecord>> GetPendingAsync(Guid userId, CancellationToken ct);
+    Task<IReadOnlyList<InAppNotificationRecord>> GetHistoryAsync(Guid userId, CancellationToken ct);
     Task<bool> AcknowledgeAsync(Guid userId, Guid notificationId, CancellationToken ct);
+    Task<int> MarkAllReadAsync(Guid userId, CancellationToken ct);
+    Task<bool> DeleteAsync(Guid userId, Guid notificationId, CancellationToken ct);
 }
 
 public sealed record InAppNotificationRecord(
     Guid Id,
     string Type,
-    string Payload,
+    string Title,
+    string Message,
+    string Severity,
+    string? ActionType,
+    string? ActionTargetId,
+    bool IsRead,
     DateTime CreatedAt);
+
+public interface IUserNotificationProducer
+{
+    Task<bool> EnqueueAsync(Guid userId, Guid sourceId, NotificationMessage message, CancellationToken ct);
+}
+
+public interface INotificationOutboxProcessor
+{
+    Task RecoverStaleAsync(CancellationToken ct);
+    Task<bool> ProcessNextAsync(CancellationToken ct);
+}