A command's output stream continues when its server pauses the sandbox

When a server paused a sandbox on its own (to make room for another sandbox, or at the end of the sandbox's time limit) while a streamed exec or a process output read was in progress, the call returned 409 sandbox_paused and the command's output was lost to the caller. The API now wakes the sandbox and resumes the call, and the command runs to its exit. This also applies to an exec sent with an Idempotency-Key (every SDK sends one), which is never run twice. A sandbox with autoWake: false still returns 409 sandbox_paused.