docs: Document valid range for idle_timeout parameter

flash/configuration/parameters.mdx

@@ -139,6 +139,7 @@ Controls worker scaling. Accepts either a single integer (max workers with min=0
 
 **Type**: `int`
 **Default**: `60`
+**Valid range**: 1-3600 seconds
 
 Number of seconds workers will stay active (running) after completing a request, waiting for additional requests before scaling down (to minimum workers).