/simplify-code findings on the #66222 salvage:
- consume_detached_task_result moves to agent/async_utils.py (shared home);
gateway/run.py and the Discord adapter both had near-identical copies of
the same pattern (a third lives in the telegram adapter). One canonical
implementation, both new callsites import it.
- Reconnect backoff formula min(30 * 2^(n-1), 300) was copied verbatim at
3 sites in run.py (primary watcher x2, secondary-profile reconnect), the
third hardcoding the cap. Hoisted to module-level _reconnect_backoff()
with a single _RECONNECT_BACKOFF_CAP so a future tune can't silently
miss one path.
Behavior-preserving: 70 gateway teardown/liveness/reconnect tests green.
c78aa0bad5