add: 使用依赖注入管理IChatRobot

添加默认实现

Frontend/Models/Chat.cs

@@ -1,8 +1,12 @@
+using Katheryne.Abstractions;
+
 namespace Frontend.Models;
 
 public class Chat
 {
     public Guid Guid { get; } = Guid.NewGuid();
+    
+    public required IChatRobot Robot { get; init; }
 
     public string Title { get; set; } = string.Empty;