Three changes to prevent sessions from getting permanently locked:
1. Agent execution timeout (HERMES_AGENT_TIMEOUT, default 10min):
Wraps run_in_executor with asyncio.wait_for so a hung API call or
runaway tool can't lock a session indefinitely. On timeout, the
agent is interrupted and the user gets an actionable error message.
2. Staleness eviction for _running_agents:
Tracks start timestamps for each session entry. When a new message
arrives and the entry is older than timeout + 1min grace, it's
evicted as a leaked lock. Safety net for any cleanup path that
fails to remove the entry.
3. Cron job timeout (HERMES_CRON_TIMEOUT, default 10min):
Wraps run_conversation in a ThreadPoolExecutor with timeout so a
hung cron job doesn't block the ticker thread (and all subsequent
cron jobs) indefinitely.
Follows grammY runner's per-update timeout pattern and aiogram's
asyncio.wait_for approach for handler deadlines.