* fix(credential-pool): clear exhaustion state on key rotation
When a user rotates an API key (e.g. via `hermes setup` after hitting a
rate limit), _upsert_entry updates the access_token on the existing pool
entry but preserves the stale last_status=exhausted from the old key.
On the next session the pool finds the entry, sees it exhausted, and
returns no usable credentials — even though the new key is valid.
Fix: when access_token changes on an existing entry, reset last_status,
last_error_code, last_error_reason, last_error_message, and
last_error_reset_at. The exhaustion state belongs to the old key, not
the new one.
* chore: add pasevin@gmail.com to AUTHOR_MAP
* fix: clear last_status_at on key rotation, remove unused pytest import
Address review feedback from teknium1 on PR #22622:
- Add last_status_at=None to the reset block (matches all other
token-sync reset paths in credential_pool.py)
- Assert last_status_at is None in the regression test
- Remove unused pytest import flagged by ruff + ty
Aleksandr Pasevin