The /new (and /reset) confirmation-button callback runs the slash-confirm
handler on the asyncio event loop (see _request_slash_confirm). That handler
calls _handle_reset_command, which invoked the SYNCHRONOUS, potentially
long-blocking _cleanup_agent_resources inline: agent.close() tears down
terminal sandboxes, browser daemons and background processes (subprocess
waits), and shutdown_memory_provider() can make a network call. A slow
teardown wedged the entire event loop, so the bot went silent and stopped
processing all messages until a manual restart.
Offload _cleanup_agent_resources via the existing contextvar-preserving
_run_in_executor_with_context helper, bounded by asyncio.wait_for with a
named _RESET_CLEANUP_TIMEOUT_S (30s). The loop is never blocked; on timeout
the reset proceeds and the worker thread is left to finish on its own (it
cannot be cancelled). The text /new path is unaffected (already off-loop).
Tests (tests/gateway/test_35994_reset_button_deadlock.py): the loop keeps
ticking while close() blocks in its worker thread; a cleanup that raises is
swallowed (warning logged) and the reset still rotates the session; a
cleanup that times out degrades gracefully. All three are mutation-verified
to fail without their respective production branch.