fix(cron): avoid live adapter reuse across event loops

[snowctl]

Summary

Cron delivery can reuse the live Matrix adapter from a different asyncio event loop. Because the adapter owns an aiohttp session, this can fail with:

Timeout context manager should be used inside a task

The failure was reproduced in a live Hermes gateway during manual execution of a Matrix-delivered cron job.

Root cause

There are two cron delivery paths involved:

• cron/scheduler.py routes gateway cron delivery through DeliveryRouter and selects the live adapter by default.
• Tool-driven Matrix delivery enters _send_to_platform(Platform.MATRIX, ...) and then _send_matrix_via_adapter().

Both paths could reuse a gateway-owned Matrix adapter from cron execution without establishing that the adapter’s HTTP session belonged to the current event loop.

The original revision of this PR changed the generic _send_via_adapter() helper, but review and live tracing showed that this was not the Matrix path. That change has been removed from this revision.

Fix

• In cron/scheduler.py, cron execution no longer selects a live runtime_adapter; it uses the standalone/ephemeral delivery path instead.
• In _send_matrix_via_adapter():
  • cron context skips live-adapter reuse;
  • foreign-loop Matrix sessions fall back to an ephemeral adapter;
  • same-loop non-cron calls continue to reuse the live adapter.

The reconnect/liveness problem for an already-connected Matrix gateway remains outside this PR.

Testing

The focused Matrix/send-message suite passes:

155 passed, 0 failed

Coverage includes the real _send_to_platform(Platform.MATRIX, ...) route for:

• cron-context fallback;
• foreign-loop fallback;
• same-loop live-adapter reuse.

Also verified:

• Python compilation for all changed modules;
• git diff --check;
• live delivery through the running Matrix gateway after reloading commit 47d1511;
• theo-daily-curiosity recorded last_status: ok with last_delivery_error: null;
• no new timeout or Matrix delivery error appeared in the gateway journal.

Tested on Linux with the repository's Hermes virtual environment.

Related work

This is the Matrix/generic cron counterpart of the event-loop mismatch documented in #18014, although that issue is WeChat-specific and already resolved on current main.

The Matrix cron delivery architecture is related to #3767 and #5271.

Scope

This PR fixes cross-event-loop reuse during cron delivery. It does not implement Matrix reconnect supervision after a dead sync/session; that is a separate failure mode and should be reviewed independently.

[teknium1]

Thanks for isolating the adapter ownership concern. The current patch is not wired into the Matrix delivery path it describes.

Problems

• Current main routes Matrix sends through _send_matrix_via_adapter in tools/send_message_tool.py:913-927. That helper directly reuses the live adapter at tools/send_message_tool.py:1693-1700, while this PR changes generic _send_via_adapter instead. The new test directly calls the generic helper, so it does not cover the actual Matrix route.
• Gateway cron startup passes the gateway loop to the scheduler (gateway/run.py:20831-20845), and live cron delivery is scheduled onto that loop in cron/scheduler.py:1627-1713. The standard gateway path therefore does not establish the reported cross-loop call into this generic helper.

Suggested changes

• Put any foreign-loop guard in _send_matrix_via_adapter before its live-adapter branch, and test via _send_to_platform(Platform.MATRIX, ...).
• Add both foreign-loop fallback and same-loop reuse coverage on that real path; then reassess whether the standalone aiohttp timeout change has a reachable caller.

Automated hermes-sweeper review.

[teknium1]

This generic fallback is not reached for Matrix: _send_to_platform dispatches Platform.MATRIX to _send_matrix_via_adapter first, and that helper still directly awaits its live adapter at current-main tools/send_message_tool.py:1693-1700. Move the loop-ownership decision to that Matrix-specific branch and test through _send_to_platform.

[snowctl]

Sorry about that, still tweaking the permissions and rules on this agent. Launched the PR without finishing our live test 🤦
Thanks for the review anyway. You were of course right: the first revision changed the generic _send_via_adapter() seam, while the Matrix route actually enters _send_matrix_via_adapter() and gateway cron delivery selects runtime_adapter in cron/scheduler.py.

I reworked it accordingly:

• cron scheduler delivery no longer selects the live adapter;
• _send_matrix_via_adapter() skips cron-context reuse and guards foreign-loop Matrix sessions;
• same-loop non-cron reuse remains unchanged;
• tests now exercise the real _send_to_platform(Platform.MATRIX, ...) route for cron fallback, foreign-loop fallback, and same-loop reuse.