Add documentation and logging improvements for MongoDB query filtering

Co-authored-by: philnach <19275540+philnach@users.noreply.github.com>

Author: Copilot

Extensions/Mongo/Cosmos.DataTransfer.MongoExtension/MongoDataSourceExtension.cs

@@ -51,6 +51,7 @@ public async IAsyncEnumerable<IDataItem> EnumerateCollectionAsync(Context contex
         }
         else
         {
+            logger.LogInformation("No query filter specified for collection '{Collection}', reading all documents", collectionName);
             // Use existing queryable approach when no filter is specified
             documents = GetAllDocumentsAsync(collection);
         }
@@ -88,6 +89,7 @@ private async IAsyncEnumerable<BsonDocument> GetQueryDocumentsAsync(IRepository<
             }
             else
             {
+                logger.LogInformation("Treating query input as direct JSON string (file does not exist): {Query}", query);
                 queryJson = query;
             }
         }

Extensions/Mongo/Cosmos.DataTransfer.MongoExtension/Settings/MongoSourceSettings.cs

@@ -5,6 +5,11 @@ public class MongoSourceSettings : MongoBaseSettings
 {
     public string? Collection { get; set; }
 
+    /// <summary>
+    /// MongoDB query filter to apply during data migration. Can be specified as:
+    /// - Direct JSON query string (e.g., "{\"field\":{\"$gte\":\"value\"}}")
+    /// - Path to a JSON file containing the query
+    /// </summary>
     public string? Query { get; set; }
 
     [SensitiveValue]