Add max Length when creating a message.

src/Web/Features/Messages/Data/Message.cs

@@ -11,5 +11,5 @@ public class Message
     [MaxLength(255)] public string? CreatedByPortraitUrl { get; set; }
     public DateTimeOffset CreatedAt { get; set; }
     public Guid? ParentId { get; set; }
-    public required string Value { get; set; }
+    [MaxLength(2048)] public required string Value { get; set; }
 }