AutoStory: story events to one shared overlay writer and to run records #159

Part of #138.

Story progress reaches the in-game overlay and run records unevenly: BDSP has its own wrapped overlay log, FRLG uses #114's status lines, and [Segment]/[Checkpoint]/[Event] lines go only to log.txt, not events.jsonl. Wire #114's story-engine status hook to one shared overlay writer (BDSP drops its own OverlayLog) and to record_run_event() from #132, with the event shape agreed between the FRLG and run-records work. Also have the recorder grab the last frame on a failure, since some steps throw without a screenshot.