Re-enable the watchfiles-based folder watcher with a Redis lock to
prevent multiple instances from stacking up across restarts. The
watcher is now automatically dispatched on startup when scanner.watch
is true (default), and only one instance runs at a time.
- Redis lock (SETNX + TTL renewal) ensures single-instance execution
- Graceful exit if another watcher holds the lock
- New POST /maintenance/start-watcher endpoint for manual control
- Fix: use settings.scanner/vision properties instead of mulita_config
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>