create cron job to check streaks

The scrapbook deployment on Vercel has a cron job that periodically hits the `/api/web/streaks` to update scrapbook user streaks.

The new Coolify deployment does not have this function yet so user streaks will not be updated unless this is fixed.

Compare the existing Vercel cron configuration with the Coolify deployment setup, using /api/web/streaks as the entry point. Confirm that the cron runs periodically against this endpoint and verify that user streaks update in the Coolify deployment.

Written by the indexing model from the issue text.