The instance status may say 'running' but the actual Docker container
may have been removed (e.g. docker prune, host restart). The old code
created a terminal session which immediately died because docker exec
failed with 'No such container'.
- Add get_container_status check in WebSocket handler before session creation
- Return 4004 with clear message if container is missing
- This prevents spawning zombie terminal sessions
alex
c7c4cb45a7