Sweep of the #119983 shape: `reasoning` had the same stale-session -> global-write
fall-through as `fast`/`yolo` (a reaped session_id wrote agent.reasoning_effort into
config.yaml and answered success), and `model` already carried its own 4001. One check
at the dispatcher replaces the three per-handler guards: a non-empty session_id this
backend no longer holds, on a key whose sessionless branch writes a wider scope
(config.yaml agent.*, the process env every later child inherits), answers 4001 so
the client resumes. `scope="global"` is still honoured; a request with no session_id
at all is still the sessionless path.
Live (temp home, stale id): base wrote reasoning_effort: high and HERMES_YOLO_MODE=1;
head leaves config.yaml and os.environ byte-identical and answers 4001 for all three.
6c2a94f4b6