The DevIndex currently uses two independent GitHub Action workflows (devindex-spider.yml and devindex-updater.yml) that run on competing 30-minute cron schedules. This leads to intermittent Git merge conflicts when both jobs attempt to modify and push tracker.json simultaneously. Furthermore, uncontrolled Spider discovery can bloat the tracker backlog.

Tasks:

1. Unify Workflows: Combine the Spider and Updater into a single, sequential pipeline (.github/workflows/devindex-pipeline.yml) that runs hourly. This guarantees atomic commits and zero git conflicts.
2. Backpressure Valve: Enhance the Spider to check the number of "pending" users (lastUpdate: null) in tracker.json. If the backlog exceeds config.spider.maxPendingUsers (e.g., 2000), the Spider should abort its discovery run to let the Updater catch up.
3. Restore 3x Loop: With the workflows unified and backpressure in place, the Spider can safely be restored to execute 3 discovery loops per hour instead of 1.
4. Cleanup: Remove the obsolete individual workflows.