feat: 后端架构重构 — Endpoint→Service→Repository分层 + AI确认机制 + 异步任务持久化

- 核心业务拆分为 Endpoint → Application Service → Repository 三层
- AI写入操作必须用户确认后才写库(确认卡片机制)
- 报告/饮食/用药分析改为持久化任务队列(原子领取/重试/重启恢复)
- 运动计划修复: 连续真实日期替代周模板
- 用药提醒去重 + 通知Outbox预留
- 认证收拢到AuthService, 管理员收拢到AdminService
- AI会话加用户归属校验防串号
- 提示词调整为患者视角
- 开发假数据已关闭
- 21/21测试通过, 0警告0错误

backend/src/Health.Application/Notifications/InAppNotificationService.cs

@@ -0,0 +1,47 @@
+using System.Text.Json;
+
+namespace Health.Application.Notifications;
+
+public sealed class InAppNotificationService(IInAppNotificationRepository notifications) : IInAppNotificationService
+{
+    private readonly IInAppNotificationRepository _notifications = notifications;
+
+    public async Task<IReadOnlyList<InAppNotificationDto>> GetPendingAsync(Guid userId, CancellationToken ct)
+    {
+        var records = await _notifications.GetPendingAsync(userId, ct);
+        return records.Select(ToDto).ToList();
+    }
+
+    public Task<bool> AcknowledgeAsync(Guid userId, Guid notificationId, CancellationToken ct) =>
+        _notifications.AcknowledgeAsync(userId, notificationId, ct);
+
+    private static InAppNotificationDto ToDto(InAppNotificationRecord record)
+    {
+        if (record.Type == "MedicationReminder")
+        {
+            using var json = JsonDocument.Parse(record.Payload);
+            var root = json.RootElement;
+            var name = root.TryGetProperty("Name", out var nameValue) ? nameValue.GetString() : null;
+            var dosage = root.TryGetProperty("Dosage", out var dosageValue) ? dosageValue.GetString() : null;
+            var time = root.TryGetProperty("ScheduledTime", out var timeValue) ? timeValue.GetString() : null;
+            var details = string.Join(" · ", new[] { dosage, time }.Where(x => !string.IsNullOrWhiteSpace(x)));
+            return new InAppNotificationDto(
+                record.Id,
+                record.Type,
+                "用药提醒",
+                $"该服用{name ?? "药物"}{(details.Length > 0 ? $"（{details}）" : "")}了",
+                record.CreatedAt);
+        }
+
+        if (record.Type == "ExerciseReminder")
+        {
+            using var json = JsonDocument.Parse(record.Payload);
+            var root = json.RootElement;
+            var type = root.TryGetProperty("ExerciseType", out var typeValue) ? typeValue.GetString() : "运动";
+            var minutes = root.TryGetProperty("DurationMinutes", out var minutesValue) ? minutesValue.GetInt32() : 30;
+            return new InAppNotificationDto(record.Id, record.Type, "运动提醒", $"今天的{type}计划还未完成，目标 {minutes} 分钟", record.CreatedAt);
+        }
+
+        return new InAppNotificationDto(record.Id, record.Type, "健康提醒", "您有一条新的健康提醒", record.CreatedAt);
+    }
+}