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/Diets/DietService.cs

@@ -0,0 +1,77 @@
+using Health.Domain.Entities;
+using Health.Domain.Enums;
+
+namespace Health.Application.Diets;
+
+public sealed class DietService(IDietRepository diets) : IDietService
+{
+    private readonly IDietRepository _diets = diets;
+
+    public async Task<IReadOnlyList<DietRecordDto>> ListAsync(Guid userId, string? date, string? mealType, CancellationToken ct)
+    {
+        var recordedAt = DateOnly.TryParse(date, out var d) ? d : (DateOnly?)null;
+        var parsedMealType = Enum.TryParse<MealType>(mealType, ignoreCase: true, out var mt) ? mt : (MealType?)null;
+
+        var records = await _diets.ListAsync(userId, recordedAt, parsedMealType, ct);
+        return records.Select(ToDto).ToList();
+    }
+
+    public async Task<Guid> CreateAsync(Guid userId, DietRecordCreateRequest request, CancellationToken ct)
+    {
+        var record = new DietRecord
+        {
+            Id = Guid.NewGuid(),
+            UserId = userId,
+            MealType = request.MealType,
+            TotalCalories = request.TotalCalories,
+            HealthScore = request.HealthScore,
+            RecordedAt = request.RecordedAt,
+            CreatedAt = DateTime.UtcNow,
+        };
+
+        foreach (var item in request.FoodItems)
+        {
+            record.FoodItems.Add(new DietFoodItem
+            {
+                Id = Guid.NewGuid(),
+                Name = item.Name,
+                Portion = item.Portion,
+                Calories = item.Calories,
+                SortOrder = item.SortOrder,
+            });
+        }
+
+        await _diets.AddAsync(record, ct);
+        await _diets.SaveChangesAsync(ct);
+        return record.Id;
+    }
+
+    public async Task<bool> DeleteAsync(Guid userId, Guid recordId, CancellationToken ct)
+    {
+        var record = await _diets.GetOwnedAsync(userId, recordId, ct);
+        if (record == null) return false;
+
+        _diets.Delete(record);
+        await _diets.SaveChangesAsync(ct);
+        return true;
+    }
+
+    public async Task<bool> UpdateAsync(Guid userId, Guid recordId, DietRecordPatchRequest request, CancellationToken ct)
+    {
+        var record = await _diets.GetOwnedAsync(userId, recordId, ct);
+        if (record == null) return false;
+
+        if (request.TotalCalories.HasValue) record.TotalCalories = request.TotalCalories.Value;
+        if (request.HealthScore.HasValue) record.HealthScore = request.HealthScore.Value;
+        await _diets.SaveChangesAsync(ct);
+        return true;
+    }
+
+    private static DietRecordDto ToDto(DietRecord record) => new(
+        record.Id,
+        record.MealType.ToString(),
+        record.TotalCalories,
+        record.HealthScore,
+        record.RecordedAt,
+        record.FoodItems.OrderBy(f => f.SortOrder).Select(f => new DietFoodItemDto(f.Name, f.Portion, f.Calories)).ToList());
+}