Add paginated user retrieval functionality in AdminController and related services. Implemented UsersFilter for filtering user queries and added LastConnectionDate property to User model. Updated database schema and frontend API to support new user management features.

src/Managing.Common/Enums.cs

@@ -544,6 +544,17 @@ public static class Enums
         UpdatedAt
     }
 
+    /// <summary>
+    /// Sortable columns for user queries
+    /// </summary>
+    public enum UserSortableColumn
+    {
+        Id,
+        Name,
+        OwnerWalletAddress,
+        AgentName
+    }
+
     /// <summary>
     /// Event types for agent summary updates
     /// </summary>