Add UserLanguage to IUserIdentity

src/Infrastructure/BotSharp.Abstraction/Users/IUserIdentity.cs

@@ -8,4 +8,5 @@ public interface IUserIdentity
     string FirstName { get; }
     string LastName { get; }
     string FullName { get; }
+    string? UserLanguage { get; }
 }

src/Infrastructure/BotSharp.Core/Users/Services/UserIdentity.cs

@@ -56,4 +56,14 @@ public class UserIdentity : IUserIdentity
             return $"{FirstName} {LastName}".Trim();
         }
     }
+
+    [JsonPropertyName("user_language")]
+    public string? UserLanguage
+    {
+        get
+        {
+            _contextAccessor.HttpContext.Request.Headers.TryGetValue("User-Language", out var languages);
+            return languages.FirstOrDefault();
+        }
+    }
 }