Add FindOnePipelineAsync method

Core.Blueprint.Mongo/Repositories/CollectionRepository.cs

@@ -248,5 +248,16 @@ namespace Core.Blueprint.Mongo
         {
             return Task.Run(() => _collection.DeleteManyAsync(filterExpression));
         }
+
+        /// <summary>
+        /// Executes an aggregation pipeline and returns the first document in the result asynchronously.
+        /// </summary>
+        /// <typeparam name="TOutput">The type of the output document you expect from the pipeline.</typeparam>
+        /// <param name="pipeline">The aggregation pipeline definition to execute.</param>
+        /// <returns>The first document from the aggregation result, or null if none found.</returns>
+        public virtual Task<TOutput> FindOnePipelineAsync<TOutput>(PipelineDefinition<TDocument, TOutput> pipeline)
+        {
+            return Task.Run(() => _collection.Aggregate(pipeline).FirstOrDefaultAsync());
+        }
     }
 }