chore: update tend workflows (0.1.11 → 0.1.12)

[prql-bot]

Automated nightly regeneration of the tend workflow files (uvx tend@latest init), picking up the upstream release.

tend version: 0.1.11 → 0.1.12

Notable changes:

• Notifications workflow now tolerates transient non-JSON gh api responses — it retries briefly, logs the actual response on failure, then skips the cycle cleanly instead of aborting the step red (fix(notifications): tolerate transient non-JSON gh api responses max-sixty/tend#780). This is the substantive body change in this diff (tend-notifications.yaml); the rest are action-ref bumps.
• list-recent-runs fails loud on transient gh errors instead of reporting a false all-clear (fix(list-recent-runs): fail loud on transient gh errors instead of a false all-clear max-sixty/tend#784).
• running-in-ci guidance refined: don't ask outsiders to do work the bot can't do itself (fix(running-in-ci): don't ask outsiders to do work the bot can't do itself max-sixty/tend#789).
• Harness timeout default raised to 5h50m (chore: bump harness timeout default to 5h50m max-sixty/tend#790).

Full upstream diff: max-sixty/tend@0.1.11...0.1.12