Add a refresh hook for external data

We should consider adding a refresh hook that runs on a cron job or is accessible via our API so that users can refresh stale, external data.

The issue does not name any files, tests, or entry points. Start by locating how external data is fetched and how the API and cron jobs are structured; clarify the refresh trigger, scope, and completion behavior before implementation. Done should include a defined refresh hook accessible through the agreed path, with tests for its behavior.

Scritto dal modello di indicizzazione a partire dal testo della issue.