Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: asmyasnikov

sql.go

@@ -214,9 +214,8 @@ func WithAutoDeclare() QueryBindConnectorOption {
 //
 //	connector, err := ydb.Connector(driver, ydb.WithCustomConverter(&MyCustomConverter{}))
 func WithCustomConverter(converter bind.Converter) QueryBindConnectorOption {
-	bind.RegisterConverter(converter)
-
-	return xsql.WithQueryBind(bind.CustomConverter{})
+	// Register the converter in a connector-scoped way by passing it as an option.
+	return xsql.WithQueryBind(bind.CustomConverter{Converter: converter})
 }
 
 // WithCustomNamedValueConverter registers a custom named value converter for database/sql query parameters
@@ -237,11 +236,9 @@ func WithCustomConverter(converter bind.Converter) QueryBindConnectorOption {
 //
 //	connector, err := ydb.Connector(driver, ydb.WithCustomNamedValueConverter(&MyNamedConverter{}))
 func WithCustomNamedValueConverter(converter bind.NamedValueConverter) QueryBindConnectorOption {
-	bind.RegisterNamedValueConverter(converter)
-
-	return xsql.WithQueryBind(bind.CustomNamedValueConverter{})
+	// Instead of global registration, return a per-connector option carrying the converter.
+	return xsql.WithQueryBind(bind.CustomNamedValueConverter{Converter: converter})
 }
-
 func WithPositionalArgs() QueryBindConnectorOption {
 	return xsql.WithQueryBind(bind.PositionalArgs{})
 }