Bug fix for DB\IO

www/lib/CoreLibs/DB/IO.php

@@ -382,7 +382,7 @@ class IO
 	/** @var array<mixed> */
 	private array $pk_name_table = [];
 	/** @var string internal primary key name, for cross calls in async */
-	private string $pk_name;
+	private string $pk_name = '';
 	/** @var bool if we use RETURNING in the INSERT call */
 	private bool $returning_id = false;
 	/** @var string if a sync is running holds the hash key of the query */