feat: 饮食记录逻辑重构 + 通知管理分隔线修复 + 多页面 UI 调整

- 饮食: 新增 DietCommentaryPolicy + diet_record_logic, 饮食记录逻辑抽取复用
- 通知管理: 分隔线改为仿通知中心样式, 跳过图标区域只留文字下方
- 侧边栏: 对话记录操作栏浮层修复 + 常用功能间距收紧
- 智能体: 欢迎卡片去 400ms 延迟 + 胶囊去阴影
- 后端: AI 会话仓库新增方法 + 饮食评论策略 + 健康记录规则调整
- 其他: api_client IP 适配 + 多页面 UI 微调 + 新增测试

backend/tests/Health.Tests/persistence_pipeline_tests.cs

@@ -1,4 +1,5 @@
 using Health.Application.Medications;
+using Health.Application.AI;
 using Health.Domain.Entities;
 using Health.Domain.Enums;
 using Health.Infrastructure.AI;
@@ -13,6 +14,50 @@ namespace Health.Tests;
 
 public sealed class PersistencePipelineTests
 {
+    [Fact]
+    public async Task ConversationCleanup_DeletesOnlyLegacyDietCommentaryArtifacts()
+    {
+        await using var db = CreateDbContext();
+        var userId = Guid.NewGuid();
+        var artifact = new Conversation
+        {
+            Id = Guid.NewGuid(),
+            UserId = userId,
+            AgentType = AgentType.Default,
+        };
+        artifact.Messages.Add(new ConversationMessage
+        {
+            Id = Guid.NewGuid(),
+            ConversationId = artifact.Id,
+            Role = MessageRole.User,
+            Content = DietCommentaryPolicy.LegacyPromptPrefix + "食物为：米饭",
+        });
+        var normal = new Conversation
+        {
+            Id = Guid.NewGuid(),
+            UserId = userId,
+            AgentType = AgentType.Default,
+        };
+        normal.Messages.Add(new ConversationMessage
+        {
+            Id = Guid.NewGuid(),
+            ConversationId = normal.Id,
+            Role = MessageRole.User,
+            Content = "请分析我今天吃的米饭",
+        });
+        db.Conversations.AddRange(artifact, normal);
+        await db.SaveChangesAsync();
+        var repository = new EfAiConversationRepository(db);
+
+        var deleted = await repository.DeleteLegacyDietCommentaryArtifactsAsync(
+            userId,
+            DietCommentaryPolicy.LegacyPromptPrefix,
+            CancellationToken.None);
+
+        Assert.Equal(1, deleted);
+        Assert.Equal(normal.Id, Assert.Single(db.Conversations).Id);
+    }
+
     [Fact]
     public async Task AiConfirmation_CanOnlyBeTakenOnceByOwner()
     {