When a persistent Docker container is removed out-of-band or a Vercel
sandbox hits a terminal state, the backend silently recreates it and
retries. The model then keeps assuming background processes and
non-persisted files from earlier commands still exist.
Backends now call _mark_recreated() after a successful recovery;
BaseEnvironment.execute() folds the one-shot flag into the result as
environment_recreated, and finalize_foreground_result() attaches a
model-facing warning field explaining what may have been lost.
Ported from lobehub/lobehub#19329 (sandbox recreation surfacing),
adapted to hermes environment backends and tool-result JSON.
a49a9d79b3