Align lifecycle page with timeout-expiry framing

Author: beran-t

docs/sandbox.mdx

@@ -3,7 +3,7 @@ title: "Sandbox lifecycle"
 sidebarTitle: Lifecycle
 ---
 
-Sandboxes stay running as long as you need them. By default, a sandbox will automatically pause after a period of inactivity to save resources — you can resume it at any time from the same state. You can also configure an explicit timeout or shut down a sandbox manually.
+Sandboxes stay running as long as you need them. When their timeout expires, they automatically pause to save resources — preserving their full state so you can resume at any time. You can also configure an explicit timeout or shut down a sandbox manually.
 
 <Info>
 Sandboxes can run continuously for up to 24 hours (Pro) or 1 hour (Base). For longer workloads, use [pause and resume](/docs/sandbox/persistence) — pausing resets the runtime window, and your sandbox's full state is preserved indefinitely.