Function effective_idle_timeout 

fn effective_idle_timeout(args: &Args) -> Duration

The idle-kill timeout to actually apply for this invocation. A declared-background call (args.declared_background, threaded from the CLI’s own run_in_background: true) is exempt from the idle-kill safety net entirely — it may legitimately go silent forever (a GUI window, a dev server) without that being a stuck/pager-hung command. Everything else keeps the ordinary idle_kill_timeout(). See issue #2491.