Self-hosted runners now wait briefly after a turn finishes before shutting down, so results aren't lost
When a self-hosted runner is told to drain (stop accepting new work and shut down), it now treats a turn that just finished as still "in flight" for a short grace period, until the session process confirms to the server that the turn has actually ended. This period is controlled by a new environment variable, SELF_HOSTED_RUNNER_POST_TURN_SETTLE_MS, which defaults to about 2 seconds. The runner's startup log now reports this setting as post-turn-settle.
Without this grace period, a runner shutting down (via SIGTERM, the signal used to stop a process) right after a turn appears complete could lose that turn's result before it was fully reported. This change closes that small window so results aren't silently dropped during a drain.