v1.0.9-beta.011 - feat: implement real-time system health diagnostics engine
- Add health-checker.ts to actively monitor drive space, library path accessibility, database backups, and stalled client downloads.
- Implement system-flags.ts to track HTTP 429 (Rate Limit) and 403 (Cloudflare) errors across ComicVine, Metron, and GetComics scrapers.
- Add a hard-stop safeguard in download-clients.ts that aborts incoming downloads if the drive has less than 2GB of free space.
- Create /api/admin/health endpoint and integrate a 15-minute automated health_check background job via BullMQ and Cron.
- Overhaul the System Health card on the Admin Dashboard to open a detailed, interactive Diagnostics Modal while preserving the quick-link to system updates.
- Update README.md to document the new diagnostic engine capabilities.
Closes #82