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/Users/UserService.cs

@@ -0,0 +1,35 @@
+namespace Health.Application.Users;
+
+public sealed class UserService(IUserRepository users) : IUserService
+{
+    private readonly IUserRepository _users = users;
+
+    public async Task<UserProfileDto?> GetProfileAsync(Guid userId, CancellationToken ct)
+    {
+        var user = await _users.GetAsync(userId, ct);
+        return user == null ? null : new UserProfileDto(
+            user.Id,
+            user.Phone,
+            user.Role,
+            user.Name,
+            user.Gender,
+            user.BirthDate?.ToString("yyyy-MM-dd"),
+            user.AvatarUrl);
+    }
+
+    public async Task<bool> UpdateProfileAsync(Guid userId, UserProfileUpdateRequest request, CancellationToken ct)
+    {
+        var user = await _users.GetAsync(userId, ct);
+        if (user == null) return false;
+
+        if (request.Name != null) user.Name = request.Name;
+        if (request.Gender != null) user.Gender = request.Gender;
+        if (request.BirthDate.HasValue) user.BirthDate = request.BirthDate.Value;
+        user.UpdatedAt = DateTime.UtcNow;
+        await _users.SaveChangesAsync(ct);
+        return true;
+    }
+
+    public Task DeleteAccountAsync(Guid userId, CancellationToken ct) =>
+        _users.DeleteAccountDataAsync(userId, ct);
+}